Low temperature polycrystalline silicon film formation with and without charged species in an electron cyclotron resonance SiH4/H2 plasma-enhanced chemical vapor deposition

Abstract

We have developed a novel technique to deposit poly-Si films on insulating substrates in an electron cyclotron resonance (ECR) SiH4/H2 plasma-enhanced chemical vapor deposition (PECVD) and investigated the effect of reactive species on polycrystalline silicon (poly-Si) film formation at low substrate temperatures. The charged species incident on the substrate were successfully shut out by using permanent magnets set above the substrate in an ECR SiH4/H2 plasma. As a result, the films formed without charged species were found to have better crystallinity than those formed with charged species at a low substrate temperature of 150 °C. From results of the atomic force microscope, it was found that the surfaces of films formed without charged species were smoother than those of films formed with charged species at a substrate temperature of 300 °C. Therefore, it was clarified that the charged species deteriorated the crystallinity and the surface roughness while the neutral reactive species played an important role for improving them in the poly-Si film formation at low temperatures using the ECR SiH4/H2 PECVD method.