CHARACTERISTICS OF SELECTIVE REACTIVE ION ETCHING OF INGAAS INALAS HETEROSTRUCTURES USING HBR PLASMA/

A highly selective reactive ion etching (RIE) process based on HBr pla sma has been demonstrated for the removal of InGaAs on InAlAs over a w ide range of plasma self-bias voltages. Etch selectivities of 160 at - 100 V and 50 at higher voltages up to - 300 V have been obtained. It is shown with the aid of x-ray photoelectron spectroscopy analysis tha t the surface residues on the etched structures can be removed by a si mple treatment in dilute HCl. No incorporation of impurities from the plasma, such as hydrogen and bromine, was detected by secondary ion ma ss spectroscopy analysis in samples treated in RIE up to - 150 V. No d egradation in mobility and sheet carrier density of the two-dimensiona l electron gas was observed in modulation-doped InAlAs/InGaAs field-ef fect transistor (FET) structures, at low self-bias voltages. The dc an d rf device parameters of FETs fabricated using RIE as the gate-recess , process compare favorably with those of corresponding devices fabric ated using a selective wet-etching process.