Low-Temperature SiO2 Layers Deposited by Combination of ECR Plasma and Supersonic Silane/Helium Jet

Abstract

As the semiconductor industry strives toward wafer postprocessing and three-dimensional integration, a demand has arisen for high-quality thin films deposited at temperatures below . In this work, we present films deposited at near room temperature, using a multipolar electron cyclotron resonance (ECR) plasma source, introducing the gas by using a high-velocity jet of silane diluted in helium. The electrical properties were studied under varying deposition parameters, such as gas flow rate, deposition pressure, and postdeposition and postmetallization annealing processes. At a low pressure, low flow and high helium flow, device-quality layers were obtained after a deposition combined with a postmetallization annealing at . These layers exhibited a refractive index of 1.46, an ratio of 2, an interface trap density in the order of , an oxide charge density down to , and a breakdown field up to . They are thus suitable as a gate dielectric in a thin-film transistor.