“Because memristors are made of the same materials used in normal integrated circuits,” says Williams, “it turns out to be very easy to integrate them with transistors.” His team, which includes HP researcher Qiangfei Xia, built a field-programmable gate array (FPGA) using a new design that includes memristors made of the semiconductor titanium dioxide and far fewer transistors than normal.
Engineers commonly use FPGAs to test prototype chip designs because they can be reconfigured to perform a wide variety of different tasks. In order to be so flexible, however, FPGAs are large and expensive. And once the design is done, engineers generally abandon FPGAs for leaner “application-specific integrated circuits.”
“When you decide what logic operation you want to do, you actually flip a bunch of switches and configuration bits in the circuit,” says Williams. In the new chip, these tasks are performed by memristors. “What we’re looking at is essentially pulling out all of the configuration bits and all of the transistor switches,” he says.
According to Williams, using memristors in FPGAs could help significantly lower costs. “If our ideas work out, this type of FPGA will completely change the balance,” he says.
Ultimately, the next few years could be very important for memristor research. Right now, “the biggest impediment to getting memristors in the marketplace is having [so few] people who can actually design circuits [using memristors],” Williams says. Still, he predicts that memristors will arrive in commercial circuits within the next three years.