ROLE OF HYDROGEN-ATOMS IN THE FORMATION PROCESS OF HYDROGENATED MICROCRYSTALLINE SILICON

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 H2plasma 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. © 1990 IOP Publishing Ltd.