Role of Hydrogen Atoms in the Formation Process of Hydrogenated Microcrystalline Silicon

Abstract

We have investigated the role of hydrogen atoms in the formation process of the hydrogenated microcrystalline silicon ( µc-Si:H) by using a layer-by-layer deposition technique in which an abundance of H atoms were supplied after the growth of every several monolayers of films. It has been found that whether or not µc-Si:H is formed is strongly dependent on the parameters (substrate temperature and waiting time before the growth of every several monolayers after H₂ plasma is turned off) which change the hydrogen coverage of the top surface. These experimental results illustrate the idea that the major role of H atoms for µc-Si:H formation is not to make “growth-zone” reactions below the top surface but to achieve sufficient hydrogen coverage of the top growing surface.