The incorporation of D, and its thermal stability in 6H-type crystals, was studied. The D was introduced either by implantation or by plasma treatment. The implantation of D was performed by using an energy of 100keV and a fluence of 2 x 1015/cm2. In as-implanted samples, a classical profile with a D density of about 1020/cm3 at a depth of about 0.75 was revealed by secondary ion mass spectrometry. Other samples were exposed to a D plasma (300C, 0.5h). It was found that, whereas the secondary ion mass spectrometric profiles of plasma-treated samples exhibited a D peak density (1020/cm3) at the surface, the background level of D was reached within less than 0.1. The samples were furnace annealed under flowing N at temperatures of up to 1000C and it was noted that, in contrast to Si and III-V materials, no significant D redistribution occurred in implanted crystals during annealing. In the case of plasma-treated samples, annealing led to a significant reduction in D.
J.M.Zavada, R.G.Wilson, F.Ren, S.J.Pearton, R.F.Davis: Solid-State Electronics, 1997, 41[5], 677-9
Table 71
Diffusivity of D in SiC
Polytype | Al (/cm3) | B (/cm3) | T (C) | D (cm2/s) | ν (/s) |
4H | 3.4 x 1016 | 9.6 x 1016 | 470 | 4.3 x 10-16 | 1.2 x 10-4 |
4H | 1.4 x 1017 | 1.4 x 1017 | 510 | 1.9 x 10-15 | 7.4 x 10-4 |
6H | 1.8 x 1016 | 8.1 x 1016 | 510 | 3.6 x 10-15 | 7.8 x 10-4 |
4H | 1.4 x 1017 | 1.4 x 1017 | 550 | 1.1 x 10-14 | 4.2 x 10-3 |
4H | 1.4 x 1017 | 1.4 x 1017 | 620 | 2.7 x 10-13 | 9.1 x 10-2 |
4H | 2.4 x 1018 | 2.0 x 1015 | 270 | 8.7 x 10-16 | 8.1 x 10-3 |
4H | 2.4 x 1018 | 2.0 x 1015 | 300 | 4.6 x 10-15 | 4.1 x 10-2 |
4H | 2.4 x 1018 | 2.0 x 1015 | 350 | 7.5 x 10-14 | 6.1 x 10-1 |
4H | 2.4 x 1018 | 2.0 x 1015 | 400 | 7.9 x 10-13 | 5.9 x 100 |