Reaction of hydrogen with chlorine during reactive ionic etching

The role of the chain mechanism of the interaction of chlorine with hydrogen in the gas phase during the reactive ionic etching (RIE) of GaAs in a CF₂Cl₂ plasma is discussed. In the presence of hydrogen, more volatile products are formed, and, as a result, the rate of etching becomes time-independent, while the boundary of etching becomes less diffuse and the etched surface appears to be smooth up to a depth of etching of >1 μm. The interaction of short-lived free radicals with the substrate is treated as heterogeneous chain termination.