In-situ dry etching of InP using phosphorus trichloride and regrowth inside a chemical beam epitaxial growth chamber

Abstract

We have extended the capability and versatility of a chemical beam epitaxial (CBE) system by demonstrating reactive chemical beam etching (CBET) of InP using phosphorus tri-chloride (PCI 3) 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 investigated CBET of InP at various substrate temperatures between ∼ 400 and 580°C, under different PCI 3 fluences, and etching conditions. Excellent surface morphology was obtained at high temperatures (≳530−570°C) and under an etching rate of ≲6 Å/s. We also found that upon addition of trimethylindium flow equivalent to a growth rate of 1 Å/s during CBET, a dramatic improvement in surface morphology was obtained even at a high net etching rate of 10 Å/s. The surface morphology obtained under such conditions is indistinguishable from that of the original substrate surface. Using SiO 2 as a mask, selective-area etching and etching followed immediately by regrowth having excellent etched and regrown morphologies were obtained. For CBET of GaAs, we employed arsenic tri-chloride (AsCl 3) in a similar manner. Furthermore, PCl 3 and AsCl 3 may be used as alternative etching gases to hydrogen chloride or carbon tetrachloride in a metalorganic vapor phase epitaxial reactor.