Raziskovalci gradijo CPU brez silicija z uporabo ogljikovih nanocevk



It is no secret that silicon manufacturing is an expensive and difficult process which requires big investment and a lot of effort to get right. Take Intel's 10 nm for example. It was originally planned to launch in 2015, but because of technical difficulties, it got delayed for 2019. That shows how silicon scaling is getting more difficult than ever, while costs are rising exponentially. Development of newer nodes is expected to cost billions of Dollars more, just for the research alone and that is not even including the costs for the setting up a manufacturing facility. In order to prepare for the moment when the development of ever-decreasing size nodes becomes financially and physically unfeasible, researchers are exploring new technologies that could replace and possibly possess even better electrical properties than silicon. One such material (actually a structure made from it) is Carbon Nanotube or CNT in short.

Raziskovalci z MIT so v sodelovanju z znanstveniki iz Analog Devices uspešno zgradili CPU, ki temelji na arhitekturi RISC-V, v celoti z uporabo CNT-jev. Ta procesor z imenom RV16X Nano trenutno izvaja samo klasičen program 'Hello World'. CNT je naravni polprevodnik, vendar se pri izdelavi izdeluje kot kovinska nanocevka. To je posledica dejstva, da se kovinske nanocevke lažje vključijo v proizvodni ekosistem. V proizvodnji ima številne izzive, ker se CNT ponavadi naključno postavijo v osi XYZ. Raziskovalci z MIT in analognih naprav so to težavo rešili tako, da so naredili dovolj velike površine, da je dovolj naključnih cevi dobro nameščenih. Procesor temelji na arhitekturi RISC-V, še posebej je zasnovan za ravnanje z 32-bitnimi navodili v 16-bitnem dizajnu širokega pomnilnika. Ker so vse faze plinovoda CPU (Instruction Fetch, Decode, Register Read, Execute in Write Back) širine 16 bitov, je CPU uradno razglašen za 16-bitni. Uporablja 14.000 logičnih vrat, kot so vrata IN ali NE, da postane popolnoma funkcionalna zasnova. Glede na skrbno manipuliranje z nanocevkami je raziskovalcem uspelo izvleči 100-odstotni izkoristek, kar pomeni, da so vsa 14.000 zapornic delovala pravilno. Tukaj je valovna oblika izvajanja programa Hello World (čeprav to ni ravno Crysis, glede na položaj te tehnologije, je zelo impresiven dosežek): The technology isn't perfect, yet. The chip ran at a very low clock speed of only 10 kHz, which means that your average CPU is an order of magnitude faster than this. With all of the flaws, this demonstration is an important achievement for the technology - a proof of concept. It shows that you are able to manufacture a working example of CPU based on something that doesn't require silicon and possibly is even better than it. We just haven't perfected all of the bits and pieces required to get CNTs at the same level of performance we already have. Sources: Nature Magazine, ArsTechnica