Formation of silicon dioxide layers at low temperatures (150—400°C) by atmospheric pressure plasma oxidation of silicon

Abstract

The formation of silicon dioxide (SiO 2 ) layers at low temperatures (150-400 1C) by atmospheric pressure plasma oxidation of Si(0 0 1) wafers have been studied using a gas mixture containing He and O 2 . A 150 MHz very high frequency (VHF) power supply was used to generate high-density atomic oxygen in the atmospheric pressure plasma. Oxidation rate, structure, and thickness and refractive index profiles of the oxidized layers were investigated by ellipsometry and infrared absorption spectroscopy. Atomic force microscopy was also employed to observe atomic-scale morphologies of the layer surface and wafer Si surface, after chemical removal of the oxidized layers. It was found that stoichiometric SiO 2 layers were obtained at higher oxidation rates than conventional dry O 2 thermal oxidation and radical oxidation processes, even at a very low substrate temperature of 150 1C. Although thickness variations were observed in the plasma region, the refractive index was independent of both substrate temperature and VHF power. In addition, the SiO 2 surface and SiO 2 /Si interface roughnesses were comparable to those obtained in conventional dry oxidation at high temperatures. r

Continuous Pore-Spanning Lipid Bilayers on Silicon Oxide-Coated Porous Substrates

“…To obtain information about the surface topography, AFM images on the nonporous parts of the SiO-coated silicon nitride substrates (Figure S1, Supporting Information) were taken (Figure B) allowing one to determine the rms surface roughness (root-mean-square, rms). A value of rms = 0.49 ± 0.03 nm (SD, n = 13) was obtained being similar to those found for silicon dioxide and gold-coated glass surfaces …”

Repulsive van der Waals Forces Self-Limit Native Oxide Growth

“…Silicon is one of the most studied materials of the modern age and is used extensively in the electronics that we use every day. Silicon oxide is used as a dielectric material in the semiconductor industry and is typically grown by surface oxidation of silicon wafers using any of several techniques, including elevated temperature, steam, ozone, plasma, etc. − The Deal–Grove model is perhaps the most common means of predicting silicon oxide growth at elevated temperatures; however, it does not apply to temperatures lower than 500 °C.…”

Ultrathin SiO2layer with a low leakage current density formed with ∼ 100% nitric acid vapor

“…For miniaturization of LSI, a decrease in thickness of gate dielectrics is indispensable, which increases the leakage current density flowing through the dielectrics. Therefore, high quality and uniform thickness are required for gate dielectrics in LSI [1]. In order to decrease a leakage current density while maintaining high capacitance, high dielectric constant materials such as HfO 2 and ZrO 2 are used for gate dielectrics [2][3][4][5][6][7][8].…”

“…The thermal oxidation method is generally used to form gate dielectrics in LSI. In the case of an ultrathin ( 1.5 nm) 1 Author to whom any correspondence should be addressed. thermal SiO 2 layer, however, a leakage current density exceeds the gate limit of 1 A cm −2 , which makes the device operation impossible [10][11][12][13].…”