Low temperature etching of GaAs substrates and improved morphology of GaAs grown by metalorganic molecular beam epitaxy using trisdimethylaminoarsenic and triethylgallium

Abstract

Metalorganic molecular beam etching of a GaAs surface is observed at temperatures as low as 370°C, for the first time, when the GaAs surface is exposed to TDMAAs (trisdimethylaminoarsenic) only. At this low temperature, not only the oxide layer is removed, but a smoothening of the surface also occurs. At higher temperatures (≥ 480° C ), however, this reaction of GaAs with TDMAAs is responsible for a roughening of the (100) GaAs surface, forming (411)A micro-facets. At low V III beam pressure ratios (≤ 0.5), smooth surfaces as well as good optical and electrical properties are obtained for GaAs layers grown even at high temperatures (550 ≤ T sub ≤ 650° C ). TDMAAs proves to be an extremely efficient arsenic source which can supply enough As even for a small V III ratio of 0.25, and provides high GaAs growth-rates up to 2 μm/h for a TDMAAs flux of 0.15 SCCM and TEG of 0.4 SCCM.