HREM study on stacking structure of SiGe/Si infrared detector①
(General Research Institute for Nonferrous Metals, Beijing100088, P.R.China)
Abstract: Stacking structure and defects in SiGe/P-Si infrared detector were studied by using localization high resolution electron microscopy (HREM). The photosensitive region in the detector consists of 3 P+-Si0.65Ge0.35layers and 2 UD-Si (undoped Si) layers. The interface between Si0.65Ge0.35and 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. Therefore the crystal defects and serious lattice deformations on the interface have not been found. A defect area with a shape of inverted triangle exists in the edge of photosensitive region. The main types of the defects in the area are stacking faults and microtwins. The stacking faults are on (1 11), and the thickness of the most microtwins is less than 4 interplanar spacing and the twin plane is (1 11). The Si0.65Ge0.35and UD-Si layers on amorphous SiO2layer consist of polycrystals grown by random nucleation, and are in wave.
Key words: heterogeneous interface; infrared detectors; high resolution electron microscopy(HREM)