Multifacet semipolar formation by controlling the groove depth via lateral sidewall epitaxy

We demonstrate InxGa1−xN/GaN light emitting diode structures with different sets of multifacet semipolar formation grown laterally on m-plane sidewalls formed by stripe patterning on preliminary grown c-plane GaN template. It was found that regrowth on shallow side walls within the GaN template resulted in a single semipolar (11¯01) facet, while deeper side walls led to multifacet semipolar formation. Very deep etching through the entire GaN template reaching the underlying sapphire substrates resulted in a combination of semipolar (11¯01) and nonpolar (11¯00) facets. The results indicate that the depth of the groove patterning can be used as a tool for controlling the set of semipolar facet formation. In addition, the growth rate in different crystallographic directions was studied and possible factors affecting the growth rates are discussed.

► Multifacet semipolar formation was found by lateral growth on m-plane sidewalls. ► Single semipolar or multi semipolar sets was controlled by groove depth. ► Different growth rate was determined in the different semipolar facets. ► Possible factors influencing the growth rates were discussed.