AlGaAs/GaAs charge injection transistor/negative resistance field-effect transistor fabricated with shallow Pd/Ge ohmic contacts

Abstract

AlGaAs/GaAs charge injection transistor (CHINT)/negative resistance field-effect transistor (NERFET) devices are fabricated with Pd/Ge ohmic contacts. Pd and Ge are deposited by e-beam evaporation. The contact metal layers are annealed by rapid thermal annealing at 450–500 °C for 1 min. This gives a shallow ohmic contact and low specific contact resistivity. The better ρc are on the order of 10−6 Ω cm2. Using Pd/Ge contacts and rapid thermal annealing method, the metallization of CHINT/NERFET becomes much less critical. Good device performance under NERFET mode and CHINT mode is achieved. The largest peak-to-valley ratio of NERFET is about 15 at room temperature. The process developed in this work considerably simplifies the fabrication of CHINT/NERFET devices.