GAS PHASE DIFFUSION AND SURFACE REACTIONS IN THE CHEMICAL VAPOUR DEPOSITION OF SILICON

Abstract

In semiconductor technology silicon is widely used as a starting material for the production of a great number of devices ranging from complicated integrated circuits to cheap solar cells. In this technology the chemical vapour deposition (CVD) of silicon plays the important role of providing the thin silicon layer in which the active devices are formed. In the growth of silicon from the vapour phase the main methods used are the hydrogen reduction of silicon halides such as SiCl4 or SiHCl3, or the decomposition of SiHl4. Various resistances are present to limit the growth rate, such as gas phase diffusion of reactants towards the interface and the surface reactions needed to arrive at the desired crystal structure. This paper deals with the nucleation of silicon, with models for high- and low temperature growth reactions and with the morphology of the resulting layers and the conditions are discussed under which monocrystalline, polycrystalline or amorphous layers can be expected.