RANGE PROFILES OF 6-10 MEV N-15 IONS IMPLANTED IN SILICON

Implantation profiles of 6 to 10 MeV N-15 ions in crystalline silicon have been investigated. Measurements of the profiles at depths from 4 to 7 mu m were rendered possible by combining the depth profiling of t he N-15 atoms through the N-15(p, alpha gamma)C-12 reaction and the ex foliation of the surface layer of the samples, accomplished by high do se He-4 ion bombardment. In this way the range profiles, measured at t he exfoliated crater bottom, could be obtained accurately without unce rtainties due to straggling of the probing proton beam. The range para meters are compared to those of Monte Carlo calculations using the ele ctronic stopping powers given by J.F. Ziegler, J.P. Biersack and U. Li ttmark [The Stopping Powers and Ranges of Ions in Matter, Vol. 1 (Perg amon, New York, 1985)]. Projected ranges were observed to be 5%-10% la rger and range stragglings 27%-6% smaller than those predicted by Mont e Carlo calculations along with the adopted stopping power parametriza tion.