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.