The channelling of incident ions, and radiation-enhanced diffusion of ion-created defects, were known to be major components of the ion-damage profile. Earlier results had revealed a deeper damage profile in InP, as compared with GaAs, when subjected to the same ion bombardment conditions. Computer simulations demonstrated that this could be attributed in part to the greater ion-channelling range in InP. The role of defect diffusion in InP was clarified here by means of experiments coupled with simulations. The multiple quantum-well probe technique was used to determine the degree of damage by measuring the change in the low-temperature photoluminescence of quantum wells before and after Ar ion bombardment. A blocking super-lattice was added to the multiple quantum-well heterostructure, and proved to be effective in preventing the damage from propagating into the material below. By correlating experimental data with computer models, an estimate of the defect diffusion constant could be obtained. The values were found to range from 4 x 10-15 to 10-14cm2/s. These high values were justified by experimental results that indicated the occurrence of radiation-enhanced diffusion during ion bombardment.

D.G.Yu, C.H.Chen, A.L.Holmes, S.P.DenBaars, E.L.Hu: Journal of Vacuum Science and Technology B, 1997, 15[6], 2672-5