HREM study on stacking structure of SiGe/Si infrared detector

Stacking structure and defects in SiGe/P-Si infrared detector were studied by using localization high resolutionelectron microscopy (HREM). The photosensitive region in the detector consists of 3 P+-Si0.65 Ge0.35 layers and 2 UD-Si(undoped Si) layers. The interface between Si0.65 Ge0.35 and UD-Si is not sharp and has a transition zone with non-uniform contrast. The misfit stress of interface is distributed gradiently along the normal direction of the interface. Thereforethe crystal defects and serious lattice deformations on the interface have not been found. A defect area with a shape of in-verted triangle exists in the edge of photosensitive region. The main types of the defects in the area are stacking faults andmicrotwins. The stacking faults are on ( 1 11), and the thickness of the most microtwins is less than 4 interplanar spacingand the twin plane is (111). The Si0.65Ge0.35 and UD-Si layers on amorphous SiO2 layer consist of polycrystals grown byrandom nueleation, and are in wave