Spectroscopic ellipsometry of germanium growth on hydrogen-terminated silicon (111)

The nucleation and coalescence of high-quality amorphous hydrogenated germanium (a-Ge:H) films produced by ArF laser-induced chemical vapor deposition on different substrates was investigated by real-time spectroscopic ellipsometry (RTSE). The ellipsometric studies reveal a significant influence of the substrate surface on the nucleation stage which, in fact, determines the optical, electronic and mechanical properties of the bulk material. Coalescence of initial clusters occurs at 16 Å film thickness for atomically smooth hydrogen-terminated c-Si(111) substrates, whereas on native oxide covered c-Si(100) substrates the bulk volume void fractions are not reached until 35 Å film thickness. The formation of Si1−xGex (x=0.12) alloy was observed on the H-terminated Si(111) interface.