Characterization and Control of Native Oxide on Silicon

Abstract

Characterization and control methods of native oxide growth on silicon (Si) surfaces at room temperature and during temperature ramp-up are described. The X-ray photoelectron spectroscopy (XPS) data have sufficient resolution to discern the stepwise increase in the amount of native oxide on hydrofluoric acid (HF)-cleaned Si surfaces exposed to air at room temperature. The native oxide growth on HF-cleaned Si surfaces can be controlled by lowering oxygen or water concentration in the ambient of the process at room temperature and by passivating the Si surface for semiconductor processes at temperatures higher than 300° C. In situ control methods of native oxide growth result in low-resistance tungsten (W)/n⁺-Si contacts and very thin oxide films with high electrical insulating performance.