High temperature processing of Czochralski grown silicon wafers can create temperature gradients high enough to generate slip. The generation of slip and the slip patterns have been found to depend on three factors: the temperature and the temperature gradient, the amount and form of the precipitated oxygen, and the direction of the initial bow and the wafer diameter over thickness ratio. A model is presented to fit experimental data of critical stress in silicon, temperature gradients, and wafer curvature to predict the critical temperature above which warpage will occur. An important result is that increased wafer diameter over thickness ratio makes the wafers more sensitive to warpage. When this is the case the difference in stresses on both sides of the wafer, because of the bending, makes the area affected by slip on the concave side much larger than on the convex side.

electrodes with surface films which are porous and rough on their solution side. Li deposition in LiPF6 solutions was found to be more uniform than in LiClO4 solutions. This correlates very well with previous studies (Fourier transform infrared, energy dispersive x-ray spectroscopy, and x-ray photoelectron spectroscopy) which revealed that different surface chemistries are developed on the electrodes in these systems.9 In LiC1O4 solutions the surface films comprise a mixture of ROCO2Li, Li2CO3, Li halides, and LiOH-Li20, while in LiPF6 solutions LiF is the major surface species. This may lead to the conclusion that the more homogeneous the composition of the surface films, the more uniform is Li deposition.

No abstract

Repeated heat treatments at 1100 °C on CZ-grown wafers result in the nucleation and growth of stacking faults in the vicinity of oxygen precipitates. During the high-temperature treatment, the precipitates and the stacking faults grow. During the cooling, new precipitates form on the SF bounding partial which by their subsequent growth can generate a ring-shaped stacking fault on top of the first one. Possible mechanisms involve interstitial condensation at the SF partial or vacancy generation by the partial climb. Models of the growth kinetics are discussed and take into account both mechanisms.