Application of NRA/channeling to study He{sup +} implanted waveguides

Four different techniques (RBS/channeling, NRA/channeling, prism coupling, and TRIM) for estimating the depth and width of a damaged layer created by ion implantation in LiNbO{sub 3} are compared. Waveguides can be created in LiNbO{sub 3} by lattice disruption damage with light ions (protons, alphas) or by implantation with Ti. End of range damage results in a decrease in refractive index that acts as a low index barrier to create a waveguide. In the electronic stopping region the ordinary index of LiNbO{sub 3} is decreased while the extraordinary index is increased. The damage in the electronic stopping regime is removed by annealing to a temperature lower than that needed to remove the nuclear damage. RBS/channeling is used to examine displacement of Nb atoms and NRA/channeling is used to study displacement of Li atoms using Li(p,{alpha}) and Li(p,{gamma}) reactions. The authors have analyzed waveguides produced by implantation of 1.7 Mev He{sup +}. Comparison of the NRA/Channeling results of as implanted and 175 C and 400 C annealed crystals suggest that electronic stopping induced lattice distortion is responsible for the increase in the extraordinary index in the electronic stopping region