OUTDIFFUSION OF IMPURITY ATOMS FROM SILICON-CRYSTALS AND ITS DEPENDENCE UPON THE ANNEALING ATMOSPHERE

The outdiffusion of boron, antimony, and phosphorus from the bare sili con wafer at 1200 degrees C, especially its dependence upon the anneal ing atmosphere, has been studied with spreading resistance and seconda ry ion mass spectroscopy (SIMS). It is found that the boron outdiffusi on proceeds when the crystal is annealed in hydrogen, but is completel y suppressed in argon even if the doping concentration is as high as 3 X10(18) cm(-3) and the annealing time is as long as 2 h. The dramatic dependence upon the atmosphere has not been observed for the other imp urities and is temporarily related with the desorption process of boro n atoms from the surface. (C) 1996 American Institute of Physics.