Chlorine Etching For In-Situ Low-Temperature Silicon Surface Cleaning For Epitaxy Applications

Chlorine in a nitrogen ambient is used to clean silicon surfaces of impurities by etching a thin layer from the surface prior to silicon epitaxial growth. Silicon etch rates of 1-10 nm/min could be achieved for temperatures from 525C to 575C. The etching of a thin layer of silicon from the surface is also capable of removing phosphorus from the surface, which conventionally is difficult to remove. Smooth surfaces and high epitaxial quality after chlorine etching are also demonstrated.