Issue link: https://iconnect007.uberflip.com/i/1185676
NOVEMBER 2019 I PCB007 MAGAZINE 37 Peterson: Yes. Currently, you can make the board and do flexible boards and all of the conductors, but not the components. Once you can do the components, then you can make fully functional boards right out of the factory with no problem, all day and night. I'd also like to point out another trend that a lot of people in the PCB design industry don't consider. Coming from the optics side of things, we talk about this all the time because there's something called photonic integrated circuits as well as the related electric photonic integrated circuits. What you will see are ful- ly functional consumer-level devices that run, partially or fully, on photonics. People are working on integrating photonics at the board level, but not photonic integrated circuits or electric photonic integrated circuits. An EPIC microprocessor from Ayar Labs came out last year; it's a great start in this direction. I don't know what the price tag is, but it's far beyond my pay grade, so it's not going to be in a consumer-level device soon, but I think it's not a matter of if; it's a matter of when. You will see regular products that you buy off the shelf that run partially or fully on photonics. Johnson: So, that's a technology shift that you're projecting. Peterson: Absolutely. This has been going on in the research community for years. People have been trying to build the fundamental cir- cuit building blocks from different photonic materials. You can do it with silicon, but there are a number of challenges; still, silicon is the best direction. All of the integrated circuits you buy are built with some type of silicon process, so you can easily adapt that to building pho- tonic integrated circuits or electric photonic in- tegrated circuits. The major challenge involves light sources and detectors that are integrated directly on silicon. One route that may be promising is super- saturated doping to build light sources and detectors. Essentially, you shift the bandgap, or remove the indirect state and the indirect bandgap, and create a direct bandgap, silicon- based semiconductor via doping. The other option is to go the germanium route and bond germanium directly onto silicon, which has its own fabrication problems. Beyond that, if you can't do those things and instead integrate it directly onto the chip level, you have to use ex- ternal components, which are bulky and create their own problems. It remains to be seen what's going to hap- pen. A couple of months ago, I talked to the father of silicon photonics, Richard Soref; he's a nice guy, and he will show you on the back of a napkin how to build all of the fundamen- tal photonic logic gates from silicon. Richard's breadth of knowledge is huge, and he was the one that told me he doesn't think III-V and II-VI semiconductors are going to do the job because they're incompatible with 1550-nanometer wavelengths; that's why the hardcore research and engineering community is looking more at silicon than at III-V and II-VI semiconductors. Johnson: What is your take on the current state of the industry and the players? How accepting are they of the fact that there's going to be a shift in the technology all around them? Peterson: It depends on who you talk to. For the more innovative manufacturers, the ones who are willing to be agile—and I use that word for a reason—adapt to change, and ex- pand their capacity are going to dutifully man- age their manufacturing capacity and balance. For example, "Do we manufacture more pho- tonics boards or traditional boards?" They're going to do it once they start seeing the real demand for it; it will happen. The PCB industry is demand-pull. A lot of what the industry does is respond to demand, The major challenge involves light sources and detectors that are integrated directly on silicon.