PROCESS OF POLYCRYSTALLINE SILICON THIN FILM

摘要

PURPOSE:To obtain a uniform polysilicon thin film by arranging a heat reflecting member so as to cover a silicon wafer arranged on a heater arranged in a vacuum vessel. CONSTITUTION:A heater 3 is arranged in a vacuum vessel 4; a silicon wafer 2 is arranged on the heater, a cage type heat reflecting plate 5 is arranged above the wafer so as to cover it; the plate 5 is equipped with gas flowing holes 5a. After the heater 3 is heated at about 600-800 deg.C while the vacuum vessel 4 is vacuumized with a diffusion pump, SiH4 gas and N2 gas are introduced, thereby producing polysilicon. By this method, the reaction efficiency of silicon material gas is increased, and a thin film can be produced by using the less amount of gas. By the effect of a heat reflecting member, processing is enabled at a temperature lower than a cold wall type; the high temperature part where gas decomposition reaction is generated is limited only in the upper part of a wafer, and therefore powder is not generated. Hence a silicon thin film excellent in uniformity can be obtained.