SiGe/Si heterostructures produced by double-energy Si+ and Ge+, and Ge+ and Ge2+ ion implantations

Abstract

Si 1−x Ge x / Si heterostructures were formed on Si(100) wafers by using single-energy Ge+ implantation, double Si+ and Ge+ implantations, or double Ge+ and Ge2+ implantations. Both near surface (hairpin dislocations) and end-of-range (EOR) damage (dislocation loops) were found. At high doses, EOR damage was found beyond the original amorphous/crystalline (a/c) interfaces after annealing. The double implantation processes using low energy and high dose Ge+ implantation to form a compositionally graded SiGe alloy layer, or using a high energy and low dose Si+ or Ge2+ implantation to form a deep amorphous layer, caused a spatial separation between the Ge maximum and a/c interface. Subsequent solid phase epitaxy anneals localized the EOR beyond the peak Ge positions. Rutherford backscattering spectroscopy channeling measurements confirm that the double-energy Ge+/Ge2+ method led to the fewest residual defects.