Analysis of Defects in Heavily-Doped MBE(Molecular-Beam Epitaxy)-GaAs

摘要

GaAs has been grown by molecular-beam epitaxy (MBE) with large concentrations (approx. 10 to the 18th power/sq. cm) of Sn, Si, Ge, and Mn as dopants. The heavily-doped n-type material has been found to contain regions of a very high dislocation density. An analysis of the less complex defect areas shows that the dislocations originate in the MBE-grown layer. These observations and others on more complex defect clusters are compared with recent studies of defects in material grown by liquid phase epitaxy (LPE). The more heavily doped p-type material contains discs of Mn-rich material at the surface of the MBE-grown epilayer. Both the structure and composition of these regions have been examined. Keywords: Crystal defects; and Impurities.