Improved morphology and crystalline quality of MBE CdZnTe/Si

We report on continuing efforts to develop a reproducible process for molecular beam epitaxy of CdZnTe on three-inch, (211) Si wafers. Through a systematic study of growth parameters, we have significantly improved the crystalline quality and have reduced the density of typical surface defects. Lower substrate growth temperatures (∼250–280°C) and higher CdZnTe growth rates improved the surface morphology of the epilayers by reducing the density of triangular surface defects. Cyclic thermal annealing was found to reduce the dislocation density. Epilayers were characterized using Nomarski microscopy, scanning electron microscopy, x-ray diffraction, defect-decoration etching, and by their use as substrates for HgCdTe epitaxy.