Effect of gas-phase processes in argon-helium-silane plasma on amorphous-nanocrystalline transition in thin films of a-Si:H

Abstract

Abstract The aim of the study is to increase the efficiency of solar cell elements on the basis of thin films of amorphous-nanocrystalline silicon, by incorporating silicon nanocrystals (SiNPs) into a film of hydrogenated amorphous silicon (a-Si:H). As a result of performing the works, a two-dimensional model of the chemical composition of plasma Ar + He/SiH4 is proposed on the basis of the system of balanced transport equations for 24 components in the discharge chamber of cylindrical geometry. It is shown that the model reasonably describes the kinetics of the chemical reactions In the PECVD reactor. Based on the calculation according to the proposed model, the densities of the main particles in the helium-argon-silane plasma of the radio-frequency capacitive (RF)-discharge are determined. It has been shown that the addition of helium to the silane plasma causes an increase in the concentration of atomic silicon. Optimal concentration of helium in the mixture is set, and a mechanism for forming silicon nanocrystals is proposed.