Diffusion and recrystallization processes during annealing of N+- and P+-implanted LiNbO3

The stability of ion irradiation induced defects and refractive index changes in LiNbO3 is examined in the temperature region 300 K <= T/sub A/ <= 1370 K using the results of RBS, volume expansion, and reflection measurements. Due to the destruction of the crystal structure the activation energy of the Li2O-diffusion in RBS-amorphous layers is reduced to (0.62 +- 0.07) eV. Thereby at temperatures T/sub A/ > 700 K a mixed phase of LiNbO3 and LiNb3O8 can be formed. The restoration of the LiNbO3 crystal structure takes place in connection with the equalization of the Li2O-concentration by diffusion from the substrate into the layer during annealing at T/sub A/ = 1370 K. (author)