Deposition and etching behaviour of boron trichloride gas at silicon surface

Abstract

The deposition and etching at a silicon surface by boron trichloride gas were overviewed in a wide temperature range using a chemical vapour deposition reactor. At temperatures lower than 800 °C, while the silicon surface was covered with boron, the formed film thickness was ignorable. At 900 °C, the boron deposition rate increased to 0.25 μm min−1. In the temperature range between 900 and 1000 °C, the boron film formation was considerable. In contrast, at 1100 °C, the silicon surface was etched at 0.36 μm min−1. At temperatures higher than 1050 °C, while etching occurred along with producing chlorosilanes, the silicon surface after the etching was still covered with boron. Boron deposition and silicon etching might simultaneously occur at high temperatures by the boron trichloride gas. By adjusting the surface temperature to 800 °C, boron and silicon co-deposition was possible using the gas mixture of dichlorosilane and boron trichloride.