ADVANCED DEVICE FABRICATION WITH ANGLED CHLORINE ION BEAM ASSISTED ETCHING.

Angled-ion-beam-assisted etching (IBAE) has been used in conjunction with a variety of lithographic techniques to produce structures in GaAs and GaAlAs with controlled side-wall geometries. In the IBAE process an argon ion beam and a jet of chlorine gas are simultaneously incident on the sample. The etching occurs due to a chemical process involving chlorine, but is highly anisotropic because of the argon ion beam. The slope of the etched wall is determined by the angle at which the sample is tilted with respect to the ion beam. A number of different side-wall contours have been generated by using fixed tilt angles and computer-controlled dynamic tilting. This technology is currently being utilized to fabricate vertical field-effect transistors (FETs), resonant tunneling transistors, surface-emitting laser arrays and quantum-wire structures. The angled IBAE technique and its use for fabricating novel devices and structures are described.