[HN Gopher] How Microchips Work
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       How Microchips Work
        
       Author : pbamotra
       Score  : 226 points
       Date   : 2024-03-17 05:17 UTC (17 hours ago)
        
 (HTM) web link (exclusivearchitecture.com)
 (TXT) w3m dump (exclusivearchitecture.com)
        
       | 0wis wrote:
       | I am not an expert but it seems like a great source to understand
       | chips without getting top deep. It reminds me the classic << Nand
       | 2 Tetris >> course [1] with less involvement indeed. Thanks for
       | the developer and thanks for sharing. Curious to know industry
       | expert comments !
       | 
       | [1]:https://www.nand2tetris.org/
        
         | nairboon wrote:
         | There is also the NandGame: https://nandgame.com/
        
       | lencastre wrote:
       | Interesting, Turing Complete is also from NAND to microcomputer.
       | 
       | [1] - https://store.steampowered.com/app/1444480/Turing_Complete/
        
       | gdevic wrote:
       | I loved the article! Spot on and just the right depth for the
       | article size (I am a CPU architect).
        
       | ww520 wrote:
       | Silicon is the perfect material for semiconductor. It has a low
       | band gap energy between the valence band and conduction band. A
       | small amount of energy, electricity applied to it, can knock its
       | outermost valence electrons off and it becomes conductive.
       | Withholding the energy, its valence electrons fall back in place
       | and it becomes non-conductive. As if by luck, silicon is
       | plentiful and cheap.
        
         | XorNot wrote:
         | This is missing one of the most important reasons though:
         | Silicon Oxide.
         | 
         | Silicon Oxide is almost perfectly lattice matched to silicon,
         | but completely insulating. Which means it's incredibly easy to
         | grow features onto polished silicon wafers because the
         | oxidation product of the material is _exactly_ what you need in
         | order to build up insulating features - i.e. MOSFET junctions,
         | capacitors and conductive paths.
        
           | kken wrote:
           | Silicon oxide grown on Si is actually amorphous, so it is not
           | lattice matched.
           | 
           | But you are complety right, the oxidation properties of Si
           | are really fortunate and ICs would have taken decades longer
           | if it were not for that. SiO2 is really the unsung hero of
           | the silicon age.
           | 
           | - SiO2 has a high bandgap and a very good insulator.
           | 
           | - It is quite inert to many chemical and gasses. (e.g.
           | germanium oxide is soluble in water, which is a headache)
           | 
           | - It can easily be grown on stoiciometric form by oxidizing
           | silicon and will form an abrupt interface to Si.
           | 
           | - The formation proceeds by diffusion of oxygen to the Si
           | interface. This is in contrast to other metal oxides, where
           | the metal will diffuse to the surface and create a
           | nonstoiciometric mixture.
           | 
           | There is no other semiconductor that forms as good an oxide.
           | Very few metals form insulating oxides on their surface, one
           | notable exception is Aluminum.
           | 
           | Edit: The famous paper that describes the SiO2 formation
           | kinetics was actually co-authored by Andy Grove, from intel
           | CEO fame.
           | 
           | https://en.wikipedia.org/wiki/Deal%E2%80%93Grove_model
        
             | stavros wrote:
             | Huh, it's as if the universe was built to make computers
             | out of.
        
               | kken wrote:
               | It's as if someone created one element that is perfectly
               | suited to build microelectronics. Sure, there are other
               | materials that improve on one property or the other, but
               | there is not a single other element which balances
               | properties as well as silicon.
               | 
               | Not even mentioned yet:
               | 
               | - Excellent mechanical properties of the single crystal
               | (think MEMS, or wafers that don't break all the time)
               | 
               | - Piezoresistive properties can be used to measure strain
               | (also quite unique due to silicon band structure)
               | 
               | - Optical properties perfectly suited to detect visible
               | light (think detectors, image sensors). Good combination
               | of band gap and carrier lifetime to build solar cells.
        
               | amelius wrote:
               | A fully optical computer would be better still.
               | 
               | https://en.wikipedia.org/wiki/Optical_computing
        
               | eternauta3k wrote:
               | It took ages from the theoretical invention of the MOS
               | transistor to us being able to grow practically good
               | enough oxides (which aren't riddled with interface
               | traps)...
        
               | stavros wrote:
               | Imagine how long it would have taken if silicon wasn't
               | this ideal.
        
               | kken wrote:
               | More like a decade, unless you refer to the Lilienfeld
               | devices.
        
               | eternauta3k wrote:
               | Yes, I was thinking of Lilienfeld. What starting point
               | are you taking?
        
               | kken wrote:
               | Bell labs tried to build a FET before the bipolar
               | transistor. It's not so clear which theory the Lilienfeld
               | devices are based on.
        
               | namaria wrote:
               | The universe is such that the computers that do exist
               | seem perfectly matched to its properties. How could it
               | not be so? Other possible universes might have completely
               | different computers and the kind we have here would be
               | unimaginable there.
        
               | stavros wrote:
               | If silicon didn't exist, our computers wouldn't seem
               | perfectly matched. It would be a struggle to make them
               | and keep them working.
        
               | namaria wrote:
               | For silicon not to exist, the universe would have to be
               | quite different. Maybe making life possible and in some
               | planet a life form might eventually find out how to build
               | computers with whatever chemistry they'd end up with. And
               | the chemistry of such a universe would seem uncannily
               | suited for such computers.
               | 
               | Point being, you can't delete an element from the
               | universe and expect everything else to be the same.
               | Silicon exists because of the physics in this universe.
               | So do silicon based computers.
        
               | layer8 wrote:
               | There is the flaw that they don't build themselves,
               | though.
        
               | arcanemachiner wrote:
               | One time I was driving around, and I thought to myself
               | "Boy, it sure is lucky we had all the products for
               | asphalt laying around, or it would have been difficult to
               | build all these roads."
               | 
               | Then I realized that if the products for building roads
               | weren't around, then we wouldn't have had those roads in
               | the first place, and I wouldn't have been reflecting on
               | how lucky we were to have all this stuff.
        
         | bee_rider wrote:
         | Clay and glass are also partially made of silicon, right?
         | 
         | I've always found of fascinating that silicon was right there
         | at the beginning of material science, and has stuck around
         | since. Same for copper.
         | 
         | I don't actually think the universe has intentions, but copper,
         | silicon, and dogs do sometimes make me question that belief, it
         | is just a little suspicious that our species would have such
         | loyal friends.
        
           | imperialdrive wrote:
           | Watch the movie Alpha some time :)
        
           | CPLX wrote:
           | It's fun to watch the Anthropic principle develop organically
           | in this sub-thread.
        
         | dogben wrote:
         | And it's relatively easy to make large pure silicon single
         | crystal.
        
       | kken wrote:
       | I am really impressed by the clarity of the illustrations in the
       | article.
        
       | xg15 wrote:
       | From the "Overview" page:
       | 
       | > _Microchips - also referred to as integrated circuits - are
       | considered to be among the greatest technological achievements of
       | the last century. Their invention has paved the way for a digital
       | revolution that keeps changing the world to the present day._
       | 
       | ...
       | 
       | > _The ENIAC computer from 1946 had over 17.000 vacuum tubes and
       | suffered a tube failure on average every two days, which was
       | time-consuming to troubleshoot and repair. With the invention of
       | the transistor in 1947 by Bell Labs, the components became
       | significantly smaller, but the transistors were still wired
       | together individually. This reduced power consumption of those
       | computers and their overall size, but not their wiring
       | complexity. It was not before the invention of integrated
       | circuits before computers became way more efficient and easier to
       | operate and maintain._
       | 
       | I find it on some level hilarious that one of the fundamental
       | breakthroughs that allowed the technological revolution pick up
       | speed and perception-wise cross the barrier from "sophisticated
       | machinery" to "magic" was, in some sense, proper cable
       | management.
        
         | jpm_sd wrote:
         | It's really /elimination/ of cable management. Essentially the
         | same thing that makes printed circuit boards superior to wire
         | wrapping. Turned a manual labor process into a
         | (photo)lithographic process. Not that different from the
         | replacement of hand-lettered manuscripts with the output of a
         | printing press!
         | 
         | In larger electronic and electromechanical systems, cables and
         | connectors ("harnessing", collectively) are still major weak
         | points.
        
       | gshubert17 wrote:
       | Just before the section on Moore's Law, it says this about
       | silicon purity:
       | 
       | > Electronic grade silicon (EG-Si): 99.9999999 pure ('nine nines
       | pure') Thats one impurity atom in every 10.000.000 silicon atoms.
       | 
       | I believe that should be 1.000.000.000 (10^9 atoms) to correspond
       | to nine nines pure. Just as one impurity atom in every 100 (10^2)
       | atoms would be 99% (two nines) pure.
        
       | imperialdrive wrote:
       | I wonder where we would be if a printed copy of that post was
       | delivered back to TI and Intel etc R&D labs 50 years ago.
        
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