In situ doped phosphorus diffusion behavior in germanium epilayer on silicon substrate by ultra-high vacuum chemical vapor deposition

Abstract

Phosphorus diffusion behaviors in in situ doped germanium epilayers on Si substrate grown in an ultra high vacuum chemical vapor deposition system at 500 °C are investigated. The phosphorus diffusion mechanism during the growth process is dominated by the extrinsic diffusion process, which can be well described with a model including a cubic dependence of diffusivity on the doping concentration. The phosphorus diffusivity into the boron-doped Ge is lower than that into the intrinsic Ge layer by about one order of magnitude. An in situ doped Ge n/p junction with rectification ratio of 1.84 × 102 is achieved by inserting an intrinsic Ge layer to avoid impurity compensation.