Nothing is the answer

Researchers in Japan have found a magic ingredient that speeds transistors:
air. Charge build-up around a transistor’s silicon “channel”—its main
electronic artery—hinders current flow. Electrically insulating this
channel with a solid insulator lowers the resistance but can lead to overheating
that fries the transistor. But now Toshiba has managed to suspend a transistor
channel above an air-filled trench that electrically insulates it. This speeds
up the transistor and lets heat escape into the air. Toshiba’s
“silicon-on-nothing” transistor will be unveiled at the Electron Devices
conference in Washington DC next week.