Graphene [Book Review]

I love my couch. And guess what I just finished doing on my couch………wait, that doesn’t sound right at all! Let’s start again.

I love cuddling on my couch with a good book. It’s a rainy day, and I was finally able to finish the last chapter (and possibly one of the most interesting ones) in my latest read Graphene.

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Graphene is an up-and-coming, possibly over-exaggerated, material in the scientific and high-tech industries. It’s a material that has interesting characteristics in conductivity, durability, and optical properties (just to name a few). Carbon fiber technology is a very rough, dirty version of the technology that still possesses some of the high strength-to-weight properties that graphene promises to improve on.

The book starts out by discussing a little bit of chemistry. Actually….. it talks a bit too much about chemistry for my taste. If you picked up this book because you are interested in graphene, you probably have had taken chemistry in college by now and will skip the first ~12 pages.

Graphene is another form of crystalline carbon. It’s a common fact that diamond is just pure carbon and is the hardest (“common”) material on earth due to its 3D atomic structure. Graphene, however, is a 2D (flat) crystalline layout made from a repeating pattern of carbon-based hexagons bound by alternating single and double bonds. This delocalizes the electrons that make up the double bonds that can freely flow through the 2D structure and result in the material’s high conductivity. See the right-most graphic in the image below:

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Graphene is more-or-less an academic curiosity in this generation, so don’t expect to see many uses for this material anytime soon. And here’s why! Most of the applications for graphene require the controlled growth of a single layer of the 2D structure or the manufacturing of very long lengths of the “film,” even if it’s a few layers high (at most).

Currently, we can mine graphene, but it comes out in a mess of tiny crystals that are meshed together in random orientations like straw in a haystack. This form is called graphite, the same stuff used in everyday pencils. It’s roughly shiny, breaks down easily, and kind-of conductive. The first experimental form of graphene evaluated was literally peeled off a piece of graphite using Scotch tape. And most of the producers of graphene just grind down “high-quality” graphite and suspend it in a liquid solution to keep these minuscule flakes separated.

It’s an interesting topic, but the layout of the book really bothered me.  The book talks about graphene and how amazing it is, but it doesn’t go into the details of these capabilities until well over halfway into the book. It talks about how to make it BEFORE the applications of the material. This irritated me more after I realized that these production processes don’t come close to what we need for these specified applications, make it mostly irrelevant. For example: tiny flakes aren’t useful for much if you have to glue them all together; the adhesive become the weakest link in the system.

There is also an entire chapter that talks about how graphene replaces most materials and just makes them better with no strong depth into HOW graphene can deliver these promises; it just lists where we can stick it. Solar panels, water filters, heaters, batteries, bandages, socks, car oil?…..you name it.

Oh….they only start using graphene symbols in the last third of the book to separate chapter sections. They just come out of nowhere.

The last few chapters actually go more into the technical details about applications and how they could be technically designed for practical uses. For example, there are 6 pages just on the topic of solar sails. It’s like a whole different author wrote that chapter. Additional topics of interest include the materials controlled conductivity (chapter 6), bio-enhanced applications (chapter 10), and nano-machines (chapter 11).

Thus, filtering through the disorganization and side rants (supply-demand, unrelated technology, patent trends?), I did obtain some interesting knowledge on the topic but still found myself still having this unsatisfied fill of info. I can’t help but feel that the authors just wanted to briefly write a book to put “book author” on their resume, and the editors received it and were like……”meh, good enough. Let’s just make some money. SOMEONE will buy it.”

Oh, don’t forget to feed your pets graphene…..this book essentially boasts the promises of the material in EVERYTHING!

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The Laws of Simplicity [Book Review]

It’s been a weird couple months for me mentally. I wasted a lot of time trying out a paid dating site. I’ve been personally obsessed with the idea of someday owning a rock climbing gym (I’m reading a book on starting a business). And of course, it’s summer time in Michigan, which means I have to enjoy the beautiful weather!

But we’re not here to listen to my life’s problems, right? We’re here to listen to me talk about a book. And it’s a relatively simple one….hence the title, The Laws of Simplicity.

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While it says “design, technology, business, life” on the front cover, the books focuses more on the human interface for the first two sections. For example, how a button layout on a remote can be rearranged to make it look less daunting. What learning curve should a user expect before mastering a “reinvented wheel” Thus, this simple book is broken down into 10 guidelines to follow with a total page count of 100 pages…..

Yes, it was designed that way. He literally ends the book with “I promise the keep it simple.”

The following ten guidelines are as follows:

  1. Reduce – Remove the clutter, or possibly hide it from view.
  2. Organize – Place like items near each other to create sub groups for easy access.
  3. Time – Reduction in waiting time, or filling dead time, invokes simplicity.
  4. Learn – If necessary, make it intuitive and rewarding for full use of the project.
  5. Difference – Some complexity is needed to give character to simple objects.
  6. Context – The background, or unused space, helps emphasize the main content.
  7. Emotion – Personalized designs can lead to an emotional connection.
  8. Trust – The device takes responsibility while freeing the user of mental burdens.
  9. Failure – We must embrace the limitations of the previous rules (1-8).
  10. The One – “Simplicity is about subtracting the obvious, and adding the meaningful.” I’m not really sure what this one truly means, but I believe it’s the over-arching mentality about designing around simplicity as a whole.

Throughout the book, there are a few illustrations to help the audience understand some of the more visual concepts that are discussed the book. For example, the image below illustrates the evolution of buttons on a typical iPod and how they have moved to an organized, intuitive appeal with less discrete parts to complete the simplicity of the final design.

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[If you want a laugh on the trackpad topic, check out The Onion’s video: https://www.youtube.com/watch?v=9BnLbv6QYcA]

In the end, I’m not sure that the book was truly worth reading. There was a lot of stuff that made sense, but it felt more like …… common sense. It would make a good “check list” if you are actually designing a product interface. However, I didn’t take away any large “life-altering” lessons that were worth remembering off the top of my head.

 

Side note:

What’s with MIT graduate/professors shamelessly advertising their Alma mater? This isn’t the first book I’ve read where this happened. The author could just say “when I was a professor……” but they don’t. They have to utilize those three letters whenever possible! Seriously, they are probably paid for this hidden advertising!

Here are some examples that I found in a couple minutes:

“….but I began my career originally as an MIT-trained engineer.” (page 38-39)

“I’ve been emailing since 1984 when I arrived at MIT as a freshmen.” (page 64)

“As an MIT undergraduate, I had managed to slip past the swimming requirement……..The return experience of learning how to swim at MIT was more successful. I admit that as a professor…..” (page 74)

“Every day some of the smartest young people in the world come to see me in my office at MIT.” (page 100)

“I used to see an older fellow at the MIT pool almost every day.” (Afterword)

 

Complications [Book Review]

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Complications: A surgeon’s notes on an imperfect science.

I need to find more books written in this type of style. A book chocked full of page-turning stories and thought-provoking narratives. It’s like watching a thriller of a man/woman about to accomplish a tremendous feat, where portions of the video cut out to flashbacks on life-changing events that sculptured the dream in which the individual is driving to complete. This book takes that feeling and applies it to surgery. This isn’t just the imperfections of what we know about the human body, but also the social implications behind the medical sciences.

The author, Atul Gawande, is a resident surgeon. A resident is someone that is fresh out of medical school and starts practicing medicine and surgery. Yes, they start practicing it. They acquired the textbook knowledge and proved that they have the mental perseverance to stick it out through 8 years of college. Then they start learning how to do specific procedures on patients.

There’s always the question of when and on whom new doctors should work on. While it’s important that residents get the experience to become the leaders of the next generation of treatment, even doctors themselves will try to avoid treatment from other residents. They are just like us, they want the best treatment for their loved ones, but they have the inside knowledge.

Even when the doctor has 1 or 20 years of experience, mistakes always happen. Each human is relatively similar, but different enough that you can never truly break every procedure from easily read statistical model. However, our society makes both doctors the ultimate fail-proof machine but will socially destroy those that do make mistakes. This makes it difficult to learn from those errors to the point that hospitals can only do it internally [Morbidity and Mortality (M&M) conferences] with a strict sense of discreteness involved. The system itself, ironically, can lead to many “burnt out” professionals, which ironically can result in the production of “bad doctors.” It’s almost a chicken-and-egg scenario of which came first.

The novel has another section devoted to the treatment of “mysteries.” This includes a lot of nerve and hormonal based diseases including unknown pain, uncontrollable blushing, and insatiable appetites. Regardless of how far we have come, there’s still a lot to learn about the human body. Due to the pressure of society for something to be done, either in the form of an easy pill or a instant-fix surgery, the medical society has implemented various forms of “experimental” procedures with some becoming norms throughout the industry (ex. gastric bypass surgery). The author pads some specific topics with the results of scientific studies, but still shows the struggles doctors face when dealing with similar topics.

The most thrilling, and my favorite, section of the book was the last third titled “Uncertainty.” It’s main theme is the interaction between the doctor and patient in terms of limited judgement, individual variation, and the doctor’s unique prior experiences.

When someone is approaching death, there are many options one can choose. However, who should be the one that has the final say? Does the doctor with the medical degree? Or the individual that has to risk possible side effects and mortal consequences? It’s this difficult balance where the patient wants the best for their future, but they may not be in the state of mind to make the best call. Individuals may know what they want, but sometimes don’t want the commitment of possibly choosing the wrong treatment and suffering the long-term guilt associated with it. Even doctors (including the author) will give up medical decision making for themselves and their family to their co-workers, knowing their decision is free from emotional stress and attachment bias.

In the other half of cases, doctors and surgeons need to convince their patients when…. or when not ….. to undergo certain procedures. Some may want to risk surgery at the cost of their life. Others may be too afraid to look into the possibility of what they may have……cancer, infections, genetic diseases. And not all decisions can be made by a supercomputer-driven algorithm crunching statistical data……”making decisions under uncertainty everyday” is what makes doctors the miracle workers that they really are. They are able to connect with their patients and reason out the best course of action for each unique individual.

I learned at a young age that I am highly susceptible to stress and what it can do to your body. Every time some sales person barks to me over some urgent matter that needs immediate attention for “the customer,” it unconsciously drives a vicious cycle of stress hormones in my body. But when it does occur, I can stop, take deep breaths, and come to the realization that no matter the outcome……. no is dying over the choices I make as an applications engineer.

That’s why I have a lot of respect for many career paths that result on the fate of people’s lives: police officers, soldiers, ……… and doctors.

 

 

 

Black Edge [Book Review]

In terms of financial investments, individuals can make money based on the knowledge behind the monetary value of various stocks. Edge is the term coined to represent this knowledge, and it has “degrees” of publicity. If you read the information in the New York Times, it was in the public domain and this white edge was safe. However, since everyone knows this information and digitization responds to public announcements almost instantaneously, you can’t make a living just off of white edge. And that’s where black edge comes in……

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Black Edge, written by Sheelah Kolhatkar, is a story behind the “inside information” that is illegal to utilize in stock market profits. Black edge can come in the form of unpublished revenues, unannounced merges, and internal project findings (medical, technical, digital) before being published in any form that can be obtained without fancy dinners, sport outings, or just general “business relationships.”

The main focus of the book is on one man, Steven Cohen, and his rise from being a son to a poor family to becoming a business owner of his own hedge fund company (SAC) as a successful billionaire “built” on an aggressive hierarchy of shady trades. The books goes into a hefty story behind the interactions between the SAC, the Securities and Exchance Commission (SEC), the FBI, and the multiple individuals involved. I won’t go into the details behind these specifics, but it does involve doctors, art auctions, FBI rivalries, an a few condemned traders (just not Cohen).

Lesson learned: If your company is going to thrive on illegal operations, make sure that there’s no links that trace yourself back to your minions doing all the dirty work.

Just sayin….

The narrative, however, does lead to many introductions into the details behind multiple topics that the audience can learn from, outside of the limitless possibilities when one becomes a billionaire. Nothing like collecting  art, right?

https://en.wikipedia.org/wiki/The_Physical_Impossibility_of_Death_in_the_Mind_of_Someone_Living

If you aren’t familiar with hedge funds, their name originally came from a technique of “hedging your bets.” You would buy stocks that you think were going well, and you would short stocks that weren’t going to do so hot. [Shorting stocks, explained in simple terms, is selling a stock that you don’t own….yet. You’d buy it later when the price (hopefully) drops]. Thus, you would return some sort of profit regardless of if the economy boomed or busted. Original hedge funds were very stable, like bank investments that looked at the long term potential, until ….. they weren’t. They just started looking at quarterly returns and then to weekly returns.

And finally, hedge funds no longer “hedged their bet”……they just traded however they liked to maximize profits. This trend took off in the financial sector and is now the huge swing in corporate American focus that everyone grumbles about today. Short term investments, at the sacrifice of the long haul. This has even led to the “demonizing” of target companies that specific individuals were planning to benefit from; publicly ridiculing (anonymous, of course) a company to force their stock prices to drastically go down (and shorted stocks to be profited from).

Black edge, thus, has been the main ingredient for this financial monster to keep dredging through the years, even after the stock market crash within the last decade. As observed through this book, it can be handled in different ways. It can be developed from a false sense of trust and relationship between individuals. It can be from a tit-for-tat trade deal, where each party is the benefit of a financial gain. But most importantly, for the legal security of the interested parties, it was treated as a Fight Club. The first rule of Fight Club………

The alternative tactic in gaining an edge over other investors is in gray edge. Something in the middle, where it feels wrong, but not bluntly wrong. While everyone will have a different sense of what would be difference between white and black intel, the only opinion that matters is the government. And even that changes over time!

The epilogue describes how recent court rulings have set a new premise in what is considered illegal trading. This involves something on the lines of……

“The benefit the leaker received in exchange for sharing the information had to be something tangible, akin to money. Friendship or favor-trading on its own was not enough.” (page 291)

People were let go, charges were dismissed, and others continued to make millions in weeks.

Personally, I don’t know what is truly right or wrong. When you think of crimes, there’s typically harm [physical, financial, social, mental] done to a specific individual or group. However, in the stock market, who is losing? It’s similar to the selling price of a house, where someone may not make that money because they were not available, physically or mentally, able to take that risk in buying/selling at the right time. Stocks, on the other hand, are so anonymous that illegal trading can feel extremely harmless……..

 

 

 

Gut [Book Review]

Everyone has heard their stomach growl. I’m currently at an airport on a Sunday after skipping breakfast, and I’m experiencing this at this exact moment. I always thought it was just one of the ways your body communicated to you when it’s an ideal time to eat again. However, this is the acoustical effect caused an internal process called the “migrating motor complex,” which is a fancy way of saying how the stomach and intestines are doing a routine cleanup of your digestive tract. The stomach releases a powerful wave into the small intestines to “sweep away” the interior walls of all residual food particles for some internal maintenance.

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This is one of the many new facts that I learned while reading Gut, by Giulia Enders. You would think that this book would be another book of boring fact as of old…..the stomach is filled with acid to break down food, the liver creates bile to help break down fats, the small intestines is made up of villi and microvilli…..blah blah blah. But it turns out there is so much more that the author gladly writes about, and she knows which facts are enticing for the audience to discover, regardless of their background. And it all starts with the topic of pooping.

What a way to capture an audience’s attention, right? The story of the cooperative tango between your two sphincters making up the rectum: one voluntary…..one involuntary. While the internal sphinctor is constantly moving material through out of your system, you have the final say when it comes to “cleaning out the back end,” regardless if it’s solid, liquid……or gas.

And don’t worry, there’s more “shit” where that came from, halfway through the book!

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Reviewing the underlying themes in this book, food digestion by itself is roughly only a third of the material. Another large chunk is the interaction between the digestive and immune systems. Tonsils are known to play a strong role in bacterial and viral detection, playing the role of a sampling center delivering a small dose of what the body can expect down the road. The appendix has been theorized to have a similar role with the additional function as a microbial warehouse that is extracted after the person has gone through diarrhea and flushed all the beneficial microbes out of their large intestines.  While the entire gastrointestinal system has many additional sites for collaboration, the tonsils and the appendix are commonly known to have the largest concentration of inflammable tissue from bacterial-immune cell interaction. Thus, these two locations tend to have a higher rate of surgical removal in our current age.

The last third of the book is on your gut micro-biome. While most of the bacterial in your body thrive in the large intestines, they also survive and have an apparent impact in your mouth (cavities), your stomach (ulcers), and your small intestines (inflammation). While bacteria are mostly associated with negative events, it’s rarely ever a parasitic relationship. Many bacteria supply assistance in the breakdown of complex molecules, the production of essential nutrients, and the regulation of hormonal balances in the body. There is evidence that these gut residences can play a significant role in their host’s mood and unconscious desires, sometimes even suicidal ones!

All of this information, including theadditional subjects not listed above, captivated my attention and flowed smoothing between chapters. While no non-fiction book is a page-turning thriller, I always looked forward to the next page in this novel.

One of the largest barriers in reading a non-fiction book is for the audience to keep track of all the unfamiliar terminology. This is not an issue here. Remember the term “migrating motor complex?” It’s only stated once, as it’s a simple name tag in case one wants to dig through a dusty, out-of-date text book that’s been waiting for some love at the bottom of your bookshelf…….sorry, old radar handbook of mine. While it does help that Gut is about the human body, a topic we are acquainted with on a daily basis, the author does take great care to remove any literary road blocks and make the eye-opening theories stand out.

I also have to bring up the illustrations throughout the book. They are all done by the author’s sister, Jill Enders. And they are a riot! They make the book seem childish at times, but they always related to the scientific text in such a creative way. Graphics in a book not just help explain the topics in a book, but they also help you remember prior chapters and allow one to look back at the work as a whole and re-navigate it if backtracking or re-capping is necessary.

As you can tell, I thoroughly enjoyed this book. If the author has another novel on the shelves, I’m definitely picking it up. Giulia has proven to me that reading her books is worth the investment, and this includes the numerous “small talk” subjects that have occurred since I started reading this book around a month ago.

 

Random fact: Sea squirts digest their own brain once they settle down…… a habit that I’m grateful that humanoids, myself included, don’t possess!

The Fabric of the Cosmos [Book Review]

Ahhh, Dr. Greene…. We meet again.

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Almost a decade ago, I read an intriguing book called The Elegant Universe. It talked about relativity, a bit on quantum physics, and then it dives headfirst into string theory. Almost too abruptly. During my undergraduate years, it became a forced struggle just to continue reading one sentence after another. When a book becomes a burden, you know it’s time to put that book down and really enjoy your free time.

When I was in NC last November, I picked up two books at the airport’s used book store. Please don’t ask me how a used book store survives the rent prices of an airport; I don’t know. Regardless, the purchase of two books are the only non-perishable items I’ve purchased at an airport. Programming the Universe, by Seth Lloyd, was the first book I’ve read and written about a few months ago. The other book, The Fabric of the Cosmos, written by Dr. Bryan Greene, is the topic of today’s post.

If you remove the glossary and notes section, this book is just shy of 500 pages long that span over 4 major topics. And oddly enough, there’s a lot of overlap between both of Greene’s novels. They both discuss the topics of relativity, quantum physics, and string theory. Halfway through this book, I started to wonder which book would have been better read first…… And due to the difficulty of the topic for most individuals, was the prior knowledge that I acquired from his first book REQUIRED for me to finish the second?

This book starts off on the topic of space. What is it? What is it referenced to? The scenario of “a rotating bucket of water” is the main referenced analogy. If you swirl a cup of wine in your hand, the liquid will accumulates at the edges leaving a curved shape on the surface.  While the notions of classical physics and relative motion are tossed around, this topic becomes a good point to introduce special (and general) relativity. The current theory is that the bucket is spinning in reference to “space-time,” this notion that space isn’t composed of ether, but it’s still there in the form of … something. Most likely fields…..like the Higgs Field. If you hit it hard enough, Higgs Bosons fly out!

And once you have talked about relativity, then it makes sense to bring up all the technical discoveries on quantum physics….and how it clashes with general relativity so much! While there is no equations or mathematical jargon in this book, the author does state that solutions utilizing both theories result in answers of infinity….or something implausible. Then, the history and idea(s) of string theory are introduced.

Yes, there’s multiple versions of string theory, and another one on top (M-Theory) that (supposedly) brings them all together.

You may wonder with all this scientific jargon ….. if it’s easy to get lost. And YES, you will find yourself re-reading multiple sections to make sure your thought process is in parallel with the authors. In parallel to that thought, being lost throughout this book is due to multiple reasons.

The first and most obvious is, of course, the fact that most of these topics go against your traditional mindset on how you perceive the universe’s outcomes. The fact that the speed of light is constant REGARDLESS of how fast you are going, still boggles my mind. The concept of a Higgs Field applies a sort of “resistance” to an object’s acceleration (and not velocity) is also intriguing.

To alleviate these inceptions, the author delivers A LOT of analogies. A frog in a bowl to represent the Higgs field. The crystalline nature of an ice cube to show entropy. Some topics even have multiple analogies to help visualize the same topic (even in the same paragraph). This may help some, but sometimes I had to sift through all the “comparable fluff” to stay on track with the current subject. Then again, depending on the reader’s background, it’s hard to tell how much is enough to truly get the main highlights across.

And numerous pictures all throughout the book help tremendously!

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Though, I must admit, there’s a point halfway though the third section (string theory), which I feel the author just gives up on this analogy strategy……especially when it comes to the topics of branes. What’s a brane? Umm……even the glossary doesn’t say. Let me check Wikipedia:

“A brane is a physical object that generalizes the notion of a point particle to higher dimensions. Branes are dynamical objects which can propagate through spacetime according to the rules of quantum mechanics. They have mass and can have other attributes such as charge.”

If I had to take a guess, branes are higher-order dimensional versions of strings (which are one dimensional) that the universe COULD be made of. They could connect the ends of strings? They could create universes (see Figure 13.8). It’s a whole new realm of mathematically robust possibilities…..

And the concept that our universe is just a holographic projection of a 2D brane where all of our pasts and futures are already known….. is an extremely unique, and unsettling, possibility.

ANYWAY…….

There is, in addition to your basic breakdown of these theories, a fourth section that I would call “quantum applications.” Time travel and teleportation are reviewed by utilizing previously discussed knowledge and implementing various scenarios which could arise. For example, a warp hole through space-time could be created that start in the same temporal slice of space-time. However, one side of the wormhole could be pushed farther into the future, but never backwards. This hypothetical situation demonstrates how EVEN IF we invent time travel in our future, they will never be able to travel back into the past to visit us NOW.

The second application, transportation, involves more-or-less the transportation of DATA, which is used to recreate a clone of the object that was “dismantled” during the measurement process. Thus, this brings up some philosophical questions, especially what is the meaning of an object? Does this mean that the original person is dead? They will be made with the same types of elements in the same orientation; they will act and behave the exact same way before “transportation.” However, they are not made with exact same elements, and they will not exist during that specified period of time during information transport…..or do they still? So many fun questions to ask that have no relevance to our age regardless the outcome. And don’t worry….. it’s only like two pages of the text.

Besides these topics, the author does cover a lot of additional topics to tie all the topics together, including entropy and the arrow of time, the cause and effect of the big bang, and quantum entanglement. And looking back at his older book, I found this work a lot more encompassing and approachable (instead of jumping straight into string theory only after a hundred pages of brief overview).

But despite the fascination that these topics can bring to mind, I’m done reading books on particle and deep theoretical physics. It’s a great mental exercises, attempting to grasp theoretical concepts that picture a stark contrast to our perceived environment. But in the end, there are a lot of theoretical guess and a lot more unknowns, all with a minimal impact on our personal lives.

Introduction to Microelectronic Fabrication

This isn’t a book review, per se. I don’t even know if this “textbook” is still available, as I found at my university’s library book sale stuffed with out-of-date textbooks. But I wanted to highlight some of the technologies written in the book.

Note: I just got done with an interview with Sandia National Labs, and this book actually helped a lot with understanding more of the fabrication capabilities and equipment they possess.

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Microfabrication, for me personally, is a very fascinating topic. By manipulating atoms, electrons, and photons in such a controlled way, one can create extremely practical devices that power the electronic needs of our everyday lifestyles. There isn’t much in terms of design theory in this book (that’s what Volume I-IV are for). However, despite being quite small (~150 pages or so), this paperback gives a precise overview of each possible process in microfabrication and the practical limitations for each. Additionally, the book is littered with (extremely beneficial) images from concept visualizations to experimental graphs to explain both procedures and parameter controls respectively.

To the fabrication methods!

Lithography

This is the general term for the method that creates a desired pattern on the wafer. By applying a thin film of radiation-sensitive polymer, one can expose the material and change its properties. Exposure is typically done with UV light, but it can also be conducted through alternative means including electron and atom beams. When exposed to an appropriate liquid (solvent), one part is removed (washed away) while the rest of the material stays. If the exposed material is dissolved, the material is known as a “positive” resist. In contrast, a “negative” resist becomes resistant to solvents when it’s exposed to radiation.

Of course, these patterns are never useful on their own. However, they create “windows” that additional processes now have access to the wafer below.

 

Etching

Etching is when you want to remove material in the lithography windows. Etching can either be done either using wet (liquid) or dry (gas/plasma) methods. The majority of etching methods are driven through chemical reactions, which allows for chemical selectivity during the etching process. Alternatively, one can create an ion beam for a pure “physical” etch that removes material through atomic bombardment, though this method is typically slower than preferred chemical etching methods.

It’s interesting to note that some etching methods (wet or dry) are directional (anisotropic) and can be used to create novel or deep trenches in your design. For example, a directional beam of atoms will remove material in the beam’s path. Other methods will selectively attack the crystal lattice row-by-row and allow unique shapes in your design.

 

Film Deposition

To add material, numerous methods are utilized to apply layers either on the atomic scale to create crystalline (epitaxial growth) layers or in “bulk” (poly-crystalline or amorphous) films (the latter being the easier and faster method). These methods include chemical vapor deposition (CVD), material sputtering, e-beam evaporation, and many others that result in thin film coatings to be applied the entire wafer.

 

Ion Diffusion & Implantation

In the making of microelectronic circuits, one wants to change the conductive properties of the Si wafer underneath all these films. That is where doping comes in, which allows for the creation of p and n doped materials necessary for diodes and transistor technology.

The easier method is to heat up the wafer environment and allow for material (vapor) to come into contact in your “window” regions of interest. Material accumulates on the surface and slowly makes it way into the wafer beneath the surface. Smaller and less interactive atoms will, of course, diffuse into the material at a faster rate.

The one thing with dopants is that they will still move around whenever the wafer is heated up in processing steps farther down the manufacturing line. Thus, one has to take into account ALL the high temperature manufacturing steps to make sure material diffusion does not get out of hand.

 

Oxidation

Sometimes, all you want to do is just change the chemical composition of the surface. The most common method is the oxidation of silicon (Si) to silicon dioxide (SiO2). SiO2 is an insulator and is a simple, yet robust barrier to many manufacturing methods. When photoresists used in lithography are not resilient enough for the required microfabrication processes, a layer of SiO2 can be grown underneath and etched to create more chemically “inert” windows.

The visually interesting aspect of growing SiO2 on Si wafers is that the wafer will change color based on the final SiO2 thickness. Thus, one can easily verify if the process went smoothly just by comparing the wafer color to a “look-up table” (but precision measurements are still used to understand your fabrication precision and consistency).

This is one of the easiest methods in a microfabrication setup, as it only involves heating up the wafers in an oven. No plasmas, no fancy chemicals. Of course, the gases present in the chamber are highly controlled as undesired chemicals can fuse to the surface and diffuse inwards when heated at such high temperatures.

Contacts & Packaging:

Finally, semiconductor chips have to be connected to the outside world and easily handled through macroscopic manufacturing processes (like being placed on a circuit board). One is typically familiar with standard processors and integrated circuits (ICs) being a black plastic box with metal leads coming out the sides or underneath. The semiconductor chip is connected to these leads typically through wire bonds “stitched” to both surfaces before the final device is completely confined in black plastic.

 

This is just a basic overview of the processes in microfabrication in this book. There are also a few additional topics on specific methods and insights for building specific designs, including BJTs (current-controlled switches) and MOSFETs (voltage-controlled switches). The last chapter details various methods on the design for MEMs (MicroElectroMechanical Systems). This is a fascinating area of research where microscopic gears, levers, springs, bridges, and many more unique shapes can be created using standard microfabrication capabilities.

After completing my 10 hour long on-site interview with Sandia, I realize that I do have a soft-spot for microfabrication. It’s a career area that I should pursue to fulfill my long-term career desires. But until then, someone has to be the sales engineer for LEDs!