AlGaAs-GaAs GATE FIELD-EFFECT TRANSISTOR
Original Publication Date: 1987-Jan-01
Included in the Prior Art Database: 2005-Jan-31
A grown AlGaAs cap is employed over GaAs in an AlGaAs-GaAs gate field- effect transistor (FET). The structure is shown in the drawing. In the drawing, a molecular beam epitaxy (MBE) in situ grown AlGaAs layer is used as a cap. This cap has the immediate advantage of much better control over its thickness and composition properties, intimate contact with the GaAs, very low stress, and ability to withstand a high temperature processing cycle. The cap is of low, about 20%, aluminum mole fraction doped AlGaAs to facilitate ohmic contact, but high enough mole fraction to obtain a good reactive ion etch (RIE) selectivity.