Boosting Ge-epi P-well mobility & crystal quality with Si or Sn implantation and melt annealing

We investigated the effects of Si, Sn and cluster-C implantation into both P-well and N-well doped regions of Ge-epi on Si wafers after laser annealing. XRD analysis shows improved Ge-epi crystallinity after >1.5J/cm2 laser melt annealing (liquid phase epitaxial regrowth) compared to sub-melt annealing (solid phase epitaxial regrowth). For the P-well case the Ge-epi Rs decreased to 1,600Q/d compared to Si at 3,4002/d suggesting a hole mobility increase of 2.1x from 150cm2/V-s to 315cmTV-s but actual measured Hall mobility was 650cm2/V-s to a depth of 60nm, an increase of 4.3x. The 1.8J/cm2 laser melt anneal with Si implant improved mobility uniformly to 700cm2/V-s to a depth of lOOnm while Sn implant improved mobility to 900cm2/V-s from the Ge-epi surface to a depth of 70nm then increases to 3000cm2/V-s at a depth of lOOnm. Measuring mobility depth profiles can be very critical in engineering surface and bulk mobility improvements which can be determined by chemical compositional changes in the Ge-epilayer especially for C where no liquid phase diffusion or movement could be detected.