Reactive ion etching of via holes for GaAs high electron mobility transistors and monolithic microwave integrated circuits using Cl2/BCl3/Ar gas mixtures

Abstract

A process for through-the-wafer via hole connections to each individual source contact for monolithic microwave and millimeter wave integrated circuits and power high electron mobility transistors has been developed using reactive ion etching in Cl2/BCl3/Ar gas mixtures. Placing vias in this manner eliminates the need for source airbridges, which minimizes source inductance and results in increased gain and efficiency. The GaAs etch rate and resultant etch profiles have been studied as functions of bias voltage, gas mixture, flow rate, via mask dimension, and etch time.