Photoelectrochemical processing of III-V semiconductors

DETAILED DESCRIPTION The invention is a process for making a semiconductor device in which intrinsic compound semiconductor material is etched by a photoelectrochemical etching procedure.
The process is useful for a variety of compound semiconductors (i.
e.
, II-VI and III-V compounds) but the III-V compounds are more extensively used.
This photoelectrochemical etching procedure requires light incident on the area being etched, an area of high conductivity (e.
g.
, metals) or p-type doping electrically attached to the surface of the semiconductor and an electrolyte that contains a suitable oxidizing agent and that dissolves the oxidation products of the III-V compound semiconductor.
The photon energy of the light should be high enough so that electron-hole pairs are created.
Generally, this requires a photon energy at least as great as the bandgap of the semiconductor.
This process produces etching only where light is incident on the semiconductor surface, in a shape, extent and rate determined by the characteristics of the incident light.
This makes possible highly accurate and precise patterns and geometric features on the semiconductor wafer.
This allows greater packing density on the wafer and more desirable device characteristics.