Boron monophosphide (BP) thin layer has been grown on Si(100) surface by using low temperature growth process. The low temperature layer is an aggregate of small crystalline particles with small inclined angles to Si(100). This layer provides nucleation centers for growing BP layer. To elucidate the effect of BP layer, GaN layer was grown on BP/Si. It has been found that cubic GaN has been successfully grown on BP laver.