Depth profile analysis of proton damage by channeling

Radiation damage existing far below a surface in silicon has been investigated by 1-MeV-proton dechanneling. An improved integral equation has been developed which is readily applied to depth analysis of the damage. Backscattering spectra are measured and analyzed for silicon irradiated with 0.8∼1.2-MeV ${\mathrm{H}}_3^{+}$ beams up to 3 × ${10}^{18}$ atoms/${\mathrm{cm}}^2$. The improved analysis gives higher damage densities at and behind damage peaks than a conventional analysis. The stopping-power ratio for silicon $〈111〉$ axial channeling is found to be 0.50±0.05 from backscattering spectra measured at different scattering angles. Damage density distributions observed are highly localized, having sharp peaks at depths slightly smaller than the irradiation proton ranges. Experimental damage profiles agree fairly well with theoretical ones based on Lindhard-Scharff Schiøtt theory with an exception that the experimental curves have much steeper slopes in front of the damage peaks.