Ion Implantation and Synthesis of Materials - Studium

100 8 Channeling4.0Silicon2.0P (microns)R max1.00.80.60.4B R max Ε 1/2 B P AmorphousRp, B Rp, P Rp, As0.20.110 20 40 60 80 100 200 400Energy (keV)Fig. 8.6. Experimental measurements of R max versus E for well-channeled ions in Si. Thedashed lines, fitted to the P data, represent an E l/2 dependence. Projected ranges, R p, of B,P, and As in amorphous Si are shown by solid lines (after Mayer et al. 1970)Rmax1 dE 2E= ∫ E= = AEN S ( E) NS ( E)0 1/2ee(8.3)where A is a constant. The relation predicted by (8.3) between R max and E 1/2 isconfirmed experimentally for well-channeled ions of B, P, As, and Sb in 〈110〉 and〈111〉 Si (see Fig. 8.6). The dashed lines are fitted representations of an E 1/2dependence. The projected ranges for B, P, and As in amorphous Si are shown bysolid lines.8.4 Dechanneling by DefectsIon channeling can also be used as a tool to examine radiation damage in ionimplanted materials. This is accomplished using high energy ions whereM1 = M2 . Typical ions used are H and He with reduced energies ε ≥ 10. Underthese conditions the scattering is Coulombic and the power-law scattering crosssectionexponent, m, has a value of 1 [see (4.19)–(4.21)].