Growth of Crystalline Silicon on a Cryogenic Substrate by Photochemical Reaction in a Condensed Phase

Abstract

We have studied photochemical deposition in a condensed phase. In the experiment, liquid silane ( SiH4) on a cryogenic substrate is irradiated with KrF and ArF excimer laser. The deposited film is characterized by Raman scattering, scanning electron microscopy, transmission electron microscopy and transmission electron diffraction. The film is composed of many rod-like crystalline silicon (c-Si) products. Their diameter and height are 400–500 nm and 500–700 nm, respectively. It is remarkable that the rod-like c-Si has grown on the cryogenic substrate. Therefore, we consider that the liquid-solid interface reaction plays an important role in the crystallization growth. In other words, the growth from the c-Si surface is necessary for crystallization. This technique solves general problems in photochemical vapor deposition techniques, such as deposition on the optical window, thermal damages of the substrate and the low deposition rate in the gas phase.