REACTIVE CHEMICAL BEAM ETCHING OF INP INSIDE A CHEMICAL BEAM EPITAXIAL-GROWTH CHAMBER USING PHOSPHORUS TRICHLORIDE

We have extended the capability and versatility of a chemical beam epi taxial (CBE) system by demonstrating reactive chemical beam etching (R CBE) of InP using phosphorus trichloride (PCl3) as the gaseous etching beam injected directly into the growth chamber. This permits instant switching from etching to growth (and vice versa) in the same run for the first time in CBE. We investigate RCBE of InP at various substrate temperatures between approximately 400 and 580-degrees-C, under diffe rent PCl3 fluences, and etching conditions. Excellent surface morpholo gy was obtained at high temperatures (greater than or similar to 530-5 70-degrees-C) and under an etching rate of less than or similar to 6 a ngstrom/s. We also found that upon addition of trimethylindium flow eq uivalent to a growth rate of 1 angstrom/s during RCBE a dramatic impro vement in surface morphology was obtained even at a high net etching r ate of 10 angstrom/s. The surface morphology obtained under such condi tions is indistinguishable from that of the original substrate surface .