Dependences of Initial Nucleation on Growth Conditions of InAs on Si by Micro-Channel Selective-Area Metal-Organic Vapor Phase Epitaxy

In order to improve the uniformity of InGaAs lateral islands on Si grown by micro-channel selective area growth, we have investigated the dependences of initial InAs nucleation on the partial pressures of trimethylindium (P(TMIn)) and tertiary butylarsine (P(TBAs)) using the in situ monitoring of surface reflectivity. The high P(TMIn) resulted in a short incubation period, a high density of nuclei, and vertical growth, suggesting that a high P(TMIn) is suitable for obtaining single nuclei in each growth area, which is vital for the growth of single-domain crystals on Si. Laterally grown InAs nuclei, which are preferable for the lateral growth of InGaAs crystals that succeeds the initial nucleation of InAs, were obtained using either a low P(TMIn) or a high P(TBAs), however, the effect of the latter was not significant. P(TBAs) did not affect the incubation period. The density, uniformity, and shape of InAs nuclei can be controlled effectively by adjusting P(TMIn), but the uniformity and lateral shape could not be obtained simultaneously. We, therefore, devised a flow-modulated sequence and obtained InAs islands that grew in the lateral direction and almost filled the growth area with a single-crystal domain. (C) 2010 The Japan Society of Applied Physics