Enhanced solid-phase crystallization of amorphous Si by plasma treatment using reactive ion etching

Solid-phase crystallization of amorphous Si (a-Si) films was found to be enhanced by oxygen- or nitrogen-plasma treatment prior to annealing for crystallization using a reactive ion etching system. Amorphous Si films were deposited by vacuum evaporation under ultrahigh-vacuum conditions. Plasma treatments were carried out using a conventional parallel-plate reactive ion etching apparatus. The incubation time for crystallization of a-Si was found to be greatly reduced by plasma treatment. Nitrogen-plasma treatment resulted in more enhanced crystallization than oxygen plasma. The incubation time was found to decrease with the increase of the self-bias voltage of the reactive ion etching system during plasma treatment. Impurity analysis suggests that metal atoms adsorbed during treatment at the surface of a-Si is one cause of the enhanced crystallization.