Selective growth on facets and in situ mask removal for regrowth

A variety of unique processing capabilities can be achieved if the use of p hotoresist can be avoided during wafer patterning. Two such processes are r eported here, based on the resistless patterning technique in which ultra-v iolet light is used to modify the surface native oxide on GaAs into a mon s table gallium oxide suitable for use as a mask. First, rye report the easy, In situ removal of the masking gallium oxide after selective growth and th en regrowth to form embedded structures without additional process steps. S econd, a non-planar GaAs wafer was exposed to ultra-violet light at an angl e so that the gallium oxide is formed everywhere except in the shadowed sid ewall areas where the native oxide remains intact. Upon thermal desorption of the native oxide, selective growth of InAs was achieved on the previousl y shadowed sidewalls only. (C) 1999 Elsevier Science B.V. All rights reserv ed.