The implantation-enhanced interdiffusion of strained heterostructures was studied by using photoluminescence, channelling, transmission electron microscopic, and secondary ion mass spectrometric methods. It was found that implantation defects diffused extensively, and annealed out during implantation. Thus, only residual extended defects remained at depths which were several times greater than the projected range. Consequently, interdiffusion occurred largely during implantation, and not during subsequent annealing; which served only to eliminate residual defects and to restore the optical properties of the heterostructures. Evidence was found for the trapping of residual defects at the interfaces, possibly due to strain, and for slower diffusion in multiple quantum wells than in bulk material. The interface-trapped defects were quite difficult to anneal out, and single quantum wells exhibited poor optical properties after implantation and annealing, while multiple quantum wells gave rise to superior photoluminescence spectra.

A.Hamoudi, E.Ligeon, J.Cibert, L.S.Dang, S.Tatarenko, G.Feuillet, P.H.Jouneau, J.L.Pautrat, K.Saminadayar: Journal of Applied Physics, 1993, 74[4], 2524-34

Figure 29

Interdiffusion in He-Rich Hg1-xCdxTe as a Function of Composition

(a: 600C, b: 550C, c: 500C, d: 450C, e: 400C, f: 350C, g: 300C)