TEMPERATURE-DEPENDENCE ON THE EMERGING CRYSTAL HABIT OF GAINP DEPOSITED ON NONPLANAR (001)GAAS SUBSTRATES

In this study the low-pressure (20 mbar) organometallic vapour phase e pitaxy (LP-OMVPE) of GaInP on nonplanar (001) GaAs substrates has been examined in the 640 degrees C-760 degrees C temperature range. Growth of this alloy on these surfaces can be characterized by low and high temperature regimes. At low temperatures (T < 720 degrees C) the growt h rate difference, between the planar and the nonplanar side walls, ar e large, and faceting features appear along the bottom corners and top edges. At the higher temperatures (T greater than or equal to 720 deg rees C) these facets are no longer present and the intra-cavity deposi tion profile follows the contour of the groove. These results have bee n compared to computer simulations of surface concentration profiles w hereby the inversely proportional relation between temperature and sup ersaturation, along with varying growth rate on adjacent surfaces of d ifferent crystallographic orientations, is found to be the driving for ce behind the occurrence of these features. The stability of the obser ved facets is related to the decrease in dangling bond densities upon surface reconstruction.