Formation mechanism of crater defects on HgCdTe/CdZnTe (211) B epilayers grown by molecular beam epitaxy

Crater defects on the surfaces of HgCdTe epilayers grown by molecular beam epitaxy have been investigated. A semiempirical model coupled with observations by transmission electron microscopy was used to analyze the defect formation mechanism. We find that Te2 dissociation plays an important role. The defect density can be controlled by adjusting growth conditions such as the substrate growth temperature, Hg flux, growth rate and composition. Tight control over the pretreatment procedures before molecular beam epitaxy growth is also necessary.