Published online by Cambridge University Press: 22 February 2011
Process technologies for self-aligned AlGaAs/GaAs and lnGaP/GaAs heterojunction bipolar transistors (HBTs) as well as dry etching fabrication schemes for submicron AlGaAs/GaAs based field effect transistors (FETs) are presented. Multiple energy F+ and H+ ions were used to isolate the active devices for HBTs. The resistance of test wafers at 200 °C showed no change over periods of 50 days. Highly selective dry and wet etch techniques for InGaP/GaAs and AlGaAs/GaAs material systems were used to uniformly expose junctions. Reliability of the alloyed ohmic contact and feasibility of the non-alloyed ohmic contact metallizations for both p and n type GaAs layers will be discussed. The reproducible gate recess etching is one of the critical steps for AlGaAs/GaAs based FETs. The etching selectivity, damage, pre and post-clean procedure were studied in terms of device performance. A simple low temperature SiNx deposition and an etch-back process with optical stepper were used to demonstrate 0.1 μm Y-shape gate feature.