HIGH-BREAKDOWN-VOLTAGE MESFET WITH A LOW-TEMPERATURE-GROWN GAAS PASSIVATION LAYER AND OVERLAPPING GATE STRUCTURE

GaAs MESFET's were fabricated using a low-temperature-grown (LTG) high-resistivity GaAs layer to passivate the doped channel between the gate and source and between the gate and drain. The gate was fabricated such that the source and drain edges of the metal gate overlapped the LTG GaAs passivation layer. The electric fields at the edges of the gate were reduced by this special combination of LTG GaAs passivation and gate geometry, resulting in a gate-drain breakdown voltage of 42 V. This value is over 60% higher than that of similar MESFET's fabricated without the gate overlap.