Chemical trapping and crystalline amorphous transition accompanying energetic proton and deuteron bombardment of silicon and germanium

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Abstract
Undoped single and polycrystalline silicon and germanium disks and internal reflection plates were bombarded with 15–38 keV H+1, D+1, H+2, and D+2 to fluences up to 2×1019 ions/cm2. The infrared and Raman local‐mode frequencies of Si–H, Si–D, Ge–H, and Ge–D were observed in the ion implanted targets. The chemical trapping efficiencies of Si and Ge for the incident ions have been determined from infrared integrated absorption intensities of the hydride and deuteride bands. The chemical trapping efficiencies for D+1 and D+2 were found to be higher than those observed for H+1 and H+2 under equal ion energy and fluence conditions. The H or D/Si and H or D/Ge atom ratios approach 2 for high fluence bombardments. A trapping mechanism to account for these observations is presented. Laser Raman scattering data showed that the surface amorphization of Si and Ge occurred to a greater extent for D+1 compared to H+1 bombardments at equal fluence and incident ion energy. Annealing of H+1, D+1, H+2, and D+2 ion implanted surface regions was monitored by the laser Raman scattering technique. The amorphous‐to‐crystalline transition was shown to occur at 630 and 480 °C for Si and Ge, respectively.