A microwave Schottky-barrier field-effect transistor

A silicon FET with a maximum frequency of oscillation f max of 10 GHz has been realized. Prime factor for the good microwave properties of the device is a newly designed gate which consists of a Schottky contact with a width of only 1 micron. This very small structure is made with the projection masking technology. The Schottky contact consists of evaporated Cr and Ni layers. Source and drain contacts are of the alloyed Au-Sb type. The channel is a thin epitaxial n-layer (d ≈ 0.2µ ρ ≈ 0.1 ohm-cm) on a high-resistive Si substrate.