A ZnS/sub 0.07/Se/sub 0.93/ metal-semiconductor field effect transistor

Abstract

We report the fabrication and test data for a n-ZnS/sub 0.07/Se/sub 0.93/ metal-semiconductor field effect transistor (MESFET). A ZnSSe FET could be a key element in opto-electronic integration employing light emitting devices, metal-semiconductor-metal photo-detectors (MSM-PD) and MESFET pre-amplifiers. Wide bandgap n-ZnS/sub 0.07/Se/sub 0.93/ is lattice-matched to the GaAs substrate and posses the "light hardness" property. A mesa active island was used to isolate devices. Source and drain (SID) ohmic contacts and gate Schottky contact were formed by Cr/In/Cr and Au, respectively. Recess etching and self-aligning techniques were adopted. Depletion mode FETs with varying gate width-to-length ratio of W/L=200 /spl mu/m/20 /spl mu/m, 200 /spl mu/m/4 /spl mu/m and 200 /spl mu/m/2 /spl mu/m were fabricated and the terminal parameters of a 2 /spl mu/m FET are as follows: the turn-on voltage, V/sub on//spl ap/1.75 V, the pinch-off voltage, V/sub P//spl ap/13 V, the unit transconductance, g/sub m/=8.73 mS/mm, and the breakdown voltage without a gate-drain bias, BV/spl ap/28 V.