Boron doping of semiconductor wafers - by diborane mixt exposure in diffusion tube followed by inert gas flushing

摘要

The boron doping of semiconductor wafers is done in a diffusion tube through which a dopant gas and a flushing gas can be passed. The wafers are first exposed for 15 mins. to the dopant gas (diborane with oxygen and argon), followed by exposure for one hour to the flushing gas (argon and/or nitrogen). This reduces the fluctuations in the layer resistance from plus-or-minus 30% with the conventional method to plus-or-minus 60%. The number of wafers has no effect on the uniformity of the result and the quality is reproducible from one charge to the next.