Reaction analysis of initial oxidation of silicon by UV-light-excited ozone and the application to rapid and uniform SiO2 film growth

UV-light-excited O3 prepared by irradiation of nearly 100% pure O3 with a KrF excimer laser (λ=248nm, irradiated area=30×10mm2) was utilized for low-temperature Si oxidation. The initial oxidation rate was determined, and the activation energy was shown to be almost zero (0.049eV). To clarify the optimum oxidation conditions, the dependence of the SiO2 film growth rate on the total photon number and the photon density was investigated. The evolution of O3 density after UV-light irradiation was experimentally measured, and the O(D1) density change is discussed. O(D1) density changes are successfully explained by using a second-order reaction model, indicating that a pulse supply of oxygen atoms is essential in the initial oxidation process. The uniform oxidation of 8in. Si wafer has been carried out using a wafer-transfer type chamber by irradiating the wafer with KrF excimer laser light expanded linearly to the wafer width by a concave lens.