(608e) Effects of Point Defects On the Oxygen Precipitates of Si Wafer Grown by Czochralski Method
AIChE Annual Meeting
Wednesday, October 19, 2011 - 4:35pm to 4:55pm
In manufacturing processes of semiconductor, the silicon wafer forms the oxygen precipitates by differences of the supersaturated oxygen concentrations. In the bulk region of a substrate, the oxygen precipitates gather the metal impurities from the active region, which mechanism is called the Intrinsic Gettering (IG). So, the IG ability of silicon wafer is very important to the production yield and performance of a device.
In the experiments, we have studied the influences of the point defect on the formation the oxygen precipitates. By changed growing conditions, we have prepared the silicon wafers which have various types of point defect. And then we calculated the concentrations of point defect. And the silicon wafers are heated by modified fabricating processes of semiconductor and then measured the distributions of oxygen precipitate. Using the simulations and measuring results, we have analyzed the reaction mechanisms by transition-state theory and surface autocatalytic reaction.
The oxygen precipitating reaction is the order shifting reaction in which the limiting reactant is oxygen. It reveals that the oxygen precipitates are formed by homogenous nucleation. However, in the present of substituted or interstitial foreign impurities, the oxygen precipitates are formed by heterogeneous nucleation. And the shifting order of the reaction is related to the concentrations of limiting reactants with respect to heat treatment conditions. And the order of reaction is in inverse proportion to the concentrations of vacancies. In the heterogeneous nucleation, the order of reaction is related to the kind of foreign atoms and concentrations of impurity.