Low-Temperature SiO2Layers Deposited by Combination of ECR Plasma and Supersonic Silane/Helium Jet

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 400°C. In this work, we present SiO2films deposited at near room temperature, using a multipolar electron cyclotron resonance (ECR) plasma source, introducing the SiH4gas 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 SiH4flow and high helium flow, device-quality SiO2layers were obtained after a deposition combined with a 5minpostmetallization annealing at 400°C. These layers exhibited a refractive index of 1.46, an O∕Siratio of 2, an interface trap density in the order of 1011cm−2eV−1, an oxide charge density down to 1010cm−2, and a breakdown field up to 11MV∕cm. They are thus suitable as a gate dielectric in a thin-film transistor.