Abstract
It is shown that exposure of a silicon substrate to sufficiently high concentrations of diborane results in a surface layer which most likely consists of a silicon‐boron phase. This phase, which is controlled by the diborane concentration and the temperature, gives rise to a prediffused layer of boron in the adjacent substrate. Good control of the phase layer affords good control of the prediffused layer. When the phase layer is removed prior to drive‐in, optimal control is achieved with respect to the final diffused structure.