Low-temperature solid-phase-crystallization in Si 1− xGe x/SiO 2

Abstract

Solid-phase crystallization (SPC) properties of Si 1− x Ge x ( x=0–0.3) layers on SiO 2 have been investigated by using ellipsometric spectroscopy. Crystallinity of the Si 1− x Ge x layers is significantly affected by both annealing-time and Ge-concentration x. The crystallinity abruptly increases at the end of the incubation time and gradually saturated during the crystallization time. As x increases, we have found that the nucleation is significantly enhanced and the estimated incubation time of x=0.3 is about 1/100 of that of pure Si ( x=0). The crystallization time defined as the time to complete SPC after nucleation also significantly decreases with increasing x. Such changes of the crystallinity in the Ge-doped Si 1− x Ge x layers perhaps originates from the difference between bond energies of SiSi, SiGe, and GeGe. The decrease of bond energy activates both nucleation and crystal-growth process in Si 1− x Ge x layers.