Effect of rapid thermal annealing on oxygen precipitation behavior in silicon wafers

The effect of rapid thermal annealing (RTA) on oxygen precipitation behavio r in Czochralski silicon wafers was investigated with an emphasis on the RT A ambient, temperature and cooling rate. It was found that (i) anomalous ox ygen precipitation (AOP) was observed in the case of RTA temperature at gre ater than or equal to 1240 degreesC with cooling rates of greater than or e qual to 25 degreesC/s in Ar and in the case of RTA temperature at greater t han or equal to 1200 degreesC with cooling rates of greater than or equal t o 5 degreesC/s in N-2, while AOP was not observed in O-2, (ii) an M-like de pth profile of precipitate density appeared for the cooling rates of greate r than or equal to 50 degreesC/s in Ar, and greater than or equal to 25 deg reesC/s in N-2, and (iii) the width-of the precipitate denuded zone was lar ger than the width of outdiffused oxygen in the case of RTA in Ar. The rela tionships of thermal equilibrium concentrations C-J* and diffusion constant s D-J were estimated to be C-1* < C-V* and D-1 > D-V (I: interstitial, V: v acancy) from the experimental results of RTA in Ar and the calculated resul ts using the Voronk-ov model.