The dependence of the diffusion coefficient upon the growth conditions of doped hydrogenated amorphous material (table 162) 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.

R.A.Street, C.C.Tsai: Philosophical Magazine B, 1988, 57[5], 663-9

 

Table 160

Diffusivity of H in Various Types of Si

 

Type

Temperature (C)

D (cm2/s)

polycrystalline

305

1.6 x 10-8

polycrystalline

245

1.1 x 10-8

polycrystalline

200

3.7 x 10-9

polycrystalline

155

9.0 x 10-10

float-zone

305

6.1 x 10-10

float-zone

245

3.1 x 10-9

float-zone

200

6.1 x 10-10

float-zone

155

1.5 x 10-10

Czochralski

305

5.6 x 10-11

Czochralski

245

9.0 x 10-10

Czochralski

200

2.0 x 10-10

Czochralski

155

4.1 x 10-11