Boron-induced redistribution of hydrogen implanted at elevated temperature into crystalline silicon

Abstract

The redistribution of hydrogen during elevated-temperature implantation of boron-pre-implanted silicon was investigated. By redistribution we mean that the final hydrogen distribution differs from the distribution of a control sample, and is attributed to sample preparation. Samples were prepared with a single boron pre-implantation, with projected range either shallower or deeper with respect to the projected range of a subsequent elevated-temperature hydrogen implantation. For shallower boron, the hydrogen redistribution was a wholesale shift in the entire distribution toward the surface, whereas for deeper boron, partial redistribution of end-of-range hydrogen toward the bulk was observed. Self-implantation experiments show that the wholesale hydrogen redistribution is not due solely to boron pre-implantation damage to the silicon lattice, but is driven by chemical effects attributed to the presence of boron.