The a-Si:H growth mechanism and the role of H abstraction from the surface by SiH3 radicals via an Eley–Rideal mechanism

The Eley–Rideal reaction scheme in which H abstraction from the a-Si:H surface takes place by SiH3 radicals directly from the gas phase is discussed as the predominant surface dangling bond creating mechanism during a-Si:H growth. As a rate-limiting step, this reaction can account for the experimentally observed temperature-independent SiH3 surface reactivity and the surface silicon–hydride composition –SiHx that changes with substrate temperature. The consequences of H abstraction via the Eley–Rideal mechanism in terms of the surface dangling bond coverage and surface diffusion processes are discussed.