Abstract
Defect microstructures within heteroepitaxiallayers are categorised according to whether they result from an inherent materials problem, are due to problems at the epilayer/substrate interface, are introduced during growth itself, or are formed during postgrowth processing. Examples are presented which include dimorphism in CdS/GaAs, twinning in epitaxial CdTe, interfacial misfit dislocationformation in ZnTe/GaAs, and interfacial phaseformation in (Cd,Zn)S/GaAs. It isfound that the development of (In, Ga)(As,P) based infrared multiple quantum well lasers grown by chemical beam epitaxy (CBE) is hindered by the limited control of the quaternary composition, as compared with gas source molecular beam epitaxy material. The use of growth interrupts to characterise gas switching procedures in CBE (In, Ga)( As,P) is described. Relaxation initiation of molecular beam epitaxy SiGe/Si structures is associated with the presence of transition metal impurities. Surface profile imaging used to investigate the first stages of defectformation is described with reference to the problem of micro twinning.
MST/3249
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