Photoluminescence techniques and repeated annealing were used to determine the diffusion coefficients for intermixing in quantum wells and to study the subsequent effects of ion implantation upon intermixing. It was shown that, after ion implantation, a very fast interdiffusion process occurred which was independent of the nature of the implanted ion and was thought to be due to the rapid diffusion of interstitials which were created during implantation. Following this rapid process, it was found that neither Ga nor Kr ions had any effect upon the subsequent interdiffusion coefficient (tables 38 and 39). After As implantation, in addition to the initial damage-related process, an enhanced region of interdiffusion was observed; with a diffusion coefficient which was an order of magnitude greater than that of an non-implanted control wafer (tables 40 and 41). This enhancement was suggested to be due to the creation of group-III vacancies by As atoms which moved into group-V lattice sites. The fast process continued until the structure had broadened by about 7.5nm, whereupon the diffusion coefficient returned to the non-implanted control value. The activation energy for interdiffusion was measured at temperatures ranging from 1050 to 750C, and a value of 3.7eV was deduced. This value was found to be independent of the nature of the implanted ion.
I.V.Bradley, W.P.Gillin, K.P.Homewood, R.P.Webb: Journal of Applied Physics, 1993, 73[4], 1686-92
Table 38
Interdiffusivity in Kr-Implanted InGaAs/GaAs
Temperature (C) | D (cm2/s) |
1050 | 7.71 x 10-15 |
1000 | 3.11 x 10-15 |
950 | 5.90 x 10-16 |
925 | 3.60 x 10-16 |
900 | 1.10 x 10-16 |
875 | 9.00 x 10-17 |
825 | 1.50 x 10-17 |
750 | 8.00 x 10-19 |
Table 39
Interdiffusivity in Ga-Implanted InGaAs/GaAs
Temperature (C) | D (cm2/s) |
1050 | 2.68 x 10-15 |
1000 | 9.10 x 10-16 |
950 | 2.20 x 10-16 |
925 | 1.30 x 10-16 |
900 | 4.10 x 10-17 |
875 | 3.10 x 10-17 |
825 | 4.30 x 10-18 |
750 | 2.00 x 10-19 |
Table 40
Interdiffusivity in Non-Implanted InGaAs/GaAs
Temperature (C) | D (cm2/s) |
1050 | 3.42 x 10-15 |
1000 | 8.45 x 10-16 |
950 | 1.97 x 10-16 |
925 | 1.77 x 10-16 |
900 | 4.25 x 10-17 |
875 | 2.27 x 10-17 |
825 | 1.00 x 10-17 |
750 | 2.00 x 10-19 |
Table 41
Interdiffusivity in As-Implanted InGaAs/GaAs
Temperature (C) | Diffusion Type | D (cm2/s) |
1050 | steady-state | 6.42 x 10-15 |
1000 | steady-state | 3.90 x 10-15 |
950 | steady-state | 6.96 x 10-16 |
950 | enhanced | 3.50 x 10-15 |
925 | steady-state | 4.50 x 10-16 |
925 | enhanced | 1.73 x 10-15 |
900 | steady-state | 3.05 x 10-16 |
900 | enhanced | 1.01 x 10-15 |
750 | enhanced | 3.30 x 10-18 |