Facet growth of AlxGa1-xAs with HCl gas by metalorganic vapor phase epitaxy

Abstract Facet growth of Al x Ga 1-x As over the entire range of Al composition with SiN x masks was successfully performed using low-pressure metalorganic vapor phase epitaxy (MOVPE). In this study, a small quantity of HCl gas was introduced into the MOVPE reactor during the selective growth in order to attain perfect selectivity. The facet shapes at the edges of the selectivity grown Al x Ga 1-x As stripes were little affected by the mask-to-window area ratio. The shape of the [0 1 1] oriented stripes was strongly affected by the Al composition. For the side facet of [0 1 1] oriented stripes with Ga-rich compositions, clear {111}A was obtained and side facet growth on {111}A plane was observed for Al-rich compositions. The side facet shape of [0 1 1] oriented AlAs stripes was strikingly influenced by changing V/III or HCl/III. On the other hand, the side facet of [011] oriented stripes was essentially {111}B for the whole Al composition. These results are discussed by considering a simple nucleation model, surface diffusion lengths of Group III atoms and production ofmetal chlorides.