Oxidation of silicon wafers under external mechanical stress was studied in this work. From the oxide thickness profile measured by an automatic ellipsometer, it was found that the oxidation kinetics of silicon was affected by the mechanical stress. The tensile stress strongly enhances the oxidation rate of silicon. A concept was proposed to explain this phenomenon by using a well-known physical Si–SiO2 lattice model. The tensile stress in the silicon will enlarge the atom spacing of silicon and make the oxidation to be easier and faster. A simulated deformation of silicon substrate under tensile stress was also given to support this concept. This work is a direct evidence of the effect of mechanical stress on silicon oxidation.

Oxidation of silicon wafers under external mechanical stress was studied in this work. From the oxide thickness profile measured by an automatic-scanning ellipsometer, it was found that the oxidation kinetics of silicon were significantly affected by mechanical stress. There are two distinct features of oxide thickness distribution corresponding to short and long times. By comparing the kinetic constants taken from experiments and the simulated stress distribution on the silicon wafer, we can possibly explain the two features of oxide thickness distribution: the initial rate constant is deformation dependent and the parabolic rate constant is stress dependent. The observed stress-dependent oxidation rates are important in the study of thin gate oxide reliability.

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Metal-oxide-semiconductor (MOS) photodetector with the high-k material enhanced deep depletion at edge was demonstrated. The mechanism of saturated substrate injection current in MOS capacitor was adopted. By building HfO2 based devices that with the direct observation of the enhanced edge charge collection efficiency due to fringing field effect in inversion, we are able to show a photodetector with 3000 times (ratio of photocurrent to dark current) improvement in sensitivity than the conventional SiO2 based tunneling photodiodes (approximate 100 times) in the visible.