An Auger investigation of the effects of rapid thermal annealing of GaAs on Si with or without intermediate Ge layers

Abstract

Scanning Auger analyses have been performed on angle lapped GaAs/Ge, Ge/Si, GaAs/Si, and GaAs/Ge/Si structures grown by vacuum evaporation and metalorganic chemical vapor deposition techniques. Elemental Auger line scans are shown to have an inherent spatial resolution of 60 Å as a result of the angle of lapping, electron beam diameter, and Auger electron escape depth. To minimize the effects of artifacts such as residual lapping and Ar+ sputtering damage and electron backscattering, the interfacial width Wi for each species i, is defined by the difference (in Å) between the point where the Auger intensity is 75% of the full intensity in that layer (Ii=0.75Ii0) and the point where the Auger intensity is 25% of the full intensity in that layer (Ii=0.25Ii0). These structures have interfaces that are 60–150 Å wide. The GaAs/Si and GaAs/Ge interfaces are broadened due to As depletion near the interface, resulting in a total interface width larger than the interface width of any individual species. Rapid thermal annealing at 900 °C for 5 s, resulted in narrower interfaces and specifically reduced the As depletion.