Quantitative analysis of thermally induced desorption during halogen-etching of a silicon (1 1 1) surface

Thermal desorption at a chlorine-adsorbed Si(1 1 1) surface was measured with high precision. High-sensitivity measurements of the temperature dependence of the isothermal process, and thermal desorption spectra (TDS) with various parameters, heating rates and levels of surface coverage, indicated that the desorption is a second-order reaction with an activation energy of 2.2 eV. The wide dynamic-range data throw light on the ability of various methods of thermal desorption measurement to describe quantitatively the surface reaction. It is important to obtain a precise energy value, which can be done by considering the whole TDS shape, as well as isothermal data, in order to distinguish various reaction processes. Our results are consistent with model calculations.