Sometimes, the ducks just line up.
Ladies and gentlemen, we have our first “space” product. (If you count middle space, that is, not the mythic outer space.) Acme Advanced Materials has produced high-grade wafers of silicon carbide, aboard flying laboratories. Why do we care?
Simply put, silicon carbide makes lots of ducks line up: SiC power switches will make components in EVs, efficient lights, wind turbines/solar arrays, and the grid in general a lot smaller and tougher, which means more efficient and inexpensive. All the way down to the wall adapters for our laptops, and possibly on into those computing devices as well. To put things in perspective: Toyota and Honda didn’t build the first hybrids until compact, efficient power switching circuits became available. Even better switches will continue our drive towards the future.
Most electronics are grown on silicon wafers; wafers are then cut into the chips that handle more and more of our lives. Chips only got practical as silicon got purified enough to take current, without heating or noise. But there’s a problem: even pure silicon only takes so much juice, without making heat and noise anyway. Enter SiC.
Silicon carbide is an alternate semiconductor material that can take far more current and heat. With more current, drivetrains add torque (“bottom end”). Better switch materials can also handle higher voltages, adding “horsepower” (top end, in electric-world) without needing multi-speed gearboxes and their complexity, weight, and volume. Conversely, existing vehicles can get smaller, lighter power controllers, especially since high-powered controllers now need cooling systems to dissipate their heat. With SiC circuitry, a liquid-cooled controller might upgrade into a fan-cooled one; a fan-cooled controller might become heat sink only.
And yes, this is highly relevant. Siemens just announced a new EV motor, with an inverter built in. The Sivetec MSA 3300 saves not only space in the drivetrain, but assembly time and thus money. If you complain that EVs cost too much, here’s your path to progress. Smaller, more tolerant equipment modules can be packaged together; a product with fewer modules and connections is then cheaper, and even more reliable. The volume freed up can then be used for other features, or simply more battery cells.
The list goes on and on: other power switches are in the charger, including charge controllers and AC/DC converters (whether that’s in the vehicle itself, or alongside), power steering motors and other major accessories, and stationary applications such as grid switches, wind turbine generators, solar inverters, and the aforementioned laptop AC/DC converters. Wouldn’t you like a wall brick that’s a fraction of the size it is now? Particularly in an airport?
So, how did Acme do this? Silicon carbide, like any semiconductor, has to be purified. Even crystal defects in a pure material have to be held to low levels, in order to conduct electricity. Acme took low-grade SiC wafers, then flew them in a metallurgical oven, aboard a plane doing roller-coaster “humps.” At the top of each hump, the plane experiences microgravity; these planes are jokingly called “vomit comets.” The oven, heating the semiconductor wafers, causes annealing- the crystal structure heals itself. Microgravity and heat combine to anneal the low-grade wafers. Back on the ground, they’re as good as the best SiC wafers from other companies and processes, but at a lower cost.
And it goes on and on: this process is scalable. Acme has just produced four-inch wafers. Electronics get cheaper when processes are reduced or eliminated, here by going to larger wafers. A larger wafer yields more chips, with the same amount of handling steps and processing time, so each chip is cheaper. There’s no reason to think Acme’s processes won’t work in the six- and eight-inch wafer diameters now preferred. Furthermore, this process is using existing planes. Right now, “vomit comets” are old airliners, refitted into flying laboratories. The semiconductor equipment isn’t large, so companies can keep installing the equipment in unused space. Or they can book rides on any number of ventures that will fly microgravity missions; this includes unmanned high-altitude planes, tourist suborbital flights, or possibly dedicated “flying ovens.”
If those wafers above look like tiny tabletops, it’s because in a sense they are. The power traces are etched into the tops; the wafers themselves carry the circuits as their “substrate.” While it’s true that there are competitors to SiC, like gallium nitride and graphene, these are often grown on a substrate of… silicon carbide! And even if gallium nitride turns out to be the power semiconductor of the future, it will be because of strong competition from SiC… possibly including microgravity annealing technology, borrowed from research into SiC like this.
The table has been set. Multiple players are awaiting a feast, one for the ages.