Inversion-mode GaInAs MISFET ring oscillators

Inversion mode, self-aligned-gate, metal-insulator-semiconductor field-effect transistors (MISFET's) have been fabricated on p-type Ga
0.47
In
0.53
As epitaxially grown on semi-insulating InP substrates. Ring-oscillator (RO) circuits were designed using enhancement-driver/ enhancement-load-type logic gates. Propagation delay as low as 50 ps was measured in a nine-stage ring oscillator (driver MISFET about 1.2-µm gate length) with a fan-in and fan-out of one. These are believed to be the first results on GaInAs inversion-mode MISFET-based digital integrated circuits.