GAINASP-INP BURIED HETEROSTRUCTURE FORMATION BY LIQUID-PHASE EPITAXY

Two-step liquid phase epitaxy is shown to be impeded in the GaInAsP system by the difficulty of achieving uniform epitaxial wetting and highly radiative interfaces. This problem is most severe on the left brace 111 right brace //I//n plane and could be due to a stoichiometric disturbance at the etched surface due to unequal dissolution rates of the crystal components. Anodization etching to a depth between 430-860 A removes this problem and permits reproducible formation of high quality epitaxial layers of InP on left brace 111 right brace //I//n planes. The effectiveness of these cleaning procedures is demonstrated by the reproducible preparation of low threshold double channel planar buried heterostructure lasers.