The dependence of the diffusion coefficient upon the growth conditions of doped hydrogenated amorphous material (table 62) was measured by using secondary ion mass spectrometry. A markedly enhanced diffusivity (4.9 x 10-13 at 240C and 4.8 x 10-15cm2/s at 240C) was found in material with a columnar microstructure, due to the preferential motion of H along the columns. Increasing the deposition temperature of non-columnar material resulted in a higher diffusion coefficient and a lower H concentration. No significant change in the diffusivity was found for different n-type dopants.
Dependence of Hydrogen Diffusion on Growth Conditions in Hydrogenated Amorphous Silicon. R.A.Street, C.C.Tsai: Philosophical Magazine B, 1988, 57[5], 663-9
Table 60
Diffusivity of H in Polycrystalline Si
Material | Source | Temperature (C) | D (cm2/s) |
LPCVD | plasma | 452 | 9.0 x 10-13 |
LPCVD | plasma | 392 | 2.1 x 10-13 |
LPCVD | plasma | 350 | 1.4 x 10-13 |
LPCVD | plasma | 325 | 8.7 x 10-14 |
LPCVD | plasma | 248 | 9.7 x 10-15 |
SSC | plasma | 452 | 3.8 x 10-13 |
SSC | plasma | 452 | 1.6 x 10-13 |
SSC | plasma | 452 | 1.4 x 10-13 |
SSC | plasma | 401 | 1.0 x 10-13 |
SSC | plasma | 350 | 7.0 x 10-13 |
SSC | plasma | 350 | 5.0 x 10-13 |
SSC | plasma | 350 | 3.8 x 10-13 |
SSC | plasma | 248 | 5.3 x 10-13 |
SSC | plasma | 248 | 3.5 x 10-13 |
SSC | plasma | 248 | 3.0 x 10-13 |
LPCVD | layer | 421 | 6.3 x 10-14 |
LPCVD | layer | 350 | 2.1 x 10-14 |
LPCVD | layer | 298 | 1.3 x 10-14 |
SSC | layer | 452 | 7.1 x 10-14 |
SSC | layer | 421 | 1.2 x 10-14 |
SSC | layer | 350 | 1.7 x 10-15 |
SSC | layer | 298 | 4.1 x 10-17 |