2-GHz 150-µW self-aligned Si MESFET logic

Self-aligned normally-off silicon MESFET devices and circuits with minimum drawn gatelengths of 200 nm, and gate-to-source, and gate-to-drain spacings of 100 nm each, have been fabricated. The newly developed high-density process is based on electron beam direct writing and reactive ion etching. Ring oscillators with serial layout, a fanout of two, and drawn gatelength of 0.9 µm, show switching speeds of 220 ps at a power dissipation of 150 µW per gate.