Evidence of dislocations for the control of roughness of highly thermal boron-doped diffused silicon layers

Silicon doped by thermal diffusion from Boron(+) solid source (concentration of similar to 8x10(19)cm(-3)) at different temperature employing both dry and wet processes was obtained for bulk micromachining applications. It could observe that the surface morphology was strong influenced by temperature and ambient-related effects are non-important. For low annealing temperature (< 1000 degrees C), the predominant effects are due to segregation phenomena of boron in silicon. At higher temperature (1100 degrees C) impurity segregation is inhibited and the defects formation becomes the main effect. For B+ diffused layers at 1100 degrees C on dry oxygen ambient for 60 min, we obtained a uniform redistribution of the defects and the size is reduced. The redistribution of the defects is correlated with the surface roughness studied by atomic force microscopy (AFM) and optical microscopy.