Strain Evolution And Dopant Activation In P-Implanted Metastable Pseudomorphic Si(100)/G(0.12)Si(0.88)

A metastable Ge0.12Si0.88 layer 265 nm thick was deposited pseudomorphically on a Si(100) substrate and then implanted with 100 keV phosphorus ions at room temperature for doses of 5 x 10(13)/cm(2) to 1.5 x 10(15)/cm(2). The ions stop within the epilayer (projected range similar to 125 nm). MeV He-4 backscattering/channeling spectrometry, transmission electron microscopy, and double-crystal x-ray diffractometry were used to characterize the damage and strain in the films. The samples were subsequently annealed in high vacuum from 400-800 degrees C for 30 min at each temperature. For the nonamorphized samples (doses of 5 and 10 x 10(13)/cm(2)), most of the implantation-induced damage and strain disappear after annealing at 400-550 degrees C, but the implanted P ions activate poorly. After annealing at 700-800 degrees C, near complete activation is achieved but the strain relaxes. For the amorphized samples (dose of 1.5 x 10(15)/cm(2)), the amorphous GeSi regrows by solid-phase epitaxy and the dopants are similar to 100% activated after annealing at 550 degrees C, but the regrown GeSi relaxes with a high density of dislocations. The strain relaxes more extensively upon annealing in an implanted sample than in a nonimplanted one, other conditions being equal. This effect is more pronounced at higher ion doses, probably due to the increased amount of damage introduced at high doses.