A study was made of the evolution of the structure of intrinsic and doped hydrogenated amorphous Si films exposed to a H plasma. For this purpose, in situ spectroscopic ellipsometry and secondary ion mass spectrometry measurements were combined. It was shown that H diffused faster in B-doped hydrogenated amorphous Si than in intrinsic samples, leading to a thicker sub-surface layer right from the early stages of H plasma exposure. At longer times, H plasma leads to the formation of a microcrystalline layer via chemical transport, but there was no evidence for crystallization of the a-Si:H substrate. Moreover, it was observed that, once the microcrystalline layer was formed, H diffused out of the sample.

Hydrogen Diffusion and Induced-Crystallization in Intrinsic and Doped Hydrogenated Amorphous Silicon Films. F.Kail, A.Hadjadj, P.Roca i Cabarrocas: Thin Solid Films, 2005, 487[1-2], 126-31

 

Table 24

Diffusivity of Various H Species in n-Type and p-Type Si

Species

Type

Temperature (C)

D (cm2/s)

Ho

p

185

5.0 x 10-12

Ho

p

185

3.6 x 10-12

Ho

p

185

4.0 x 10-12

Ho

p

165

7.5 x 10-13

Ho

p

150

3.6 x 10-13

Ho

p

150

3.5 x 10-13

Ho

p

145

2.5 x 10-13

Ho

p

120

4.0 x 10-14

H+

p

185

3.0 x 10-11

H+

p

185

1.0 x 10-12

H+

p

185

1.3 x 10-14

H+

p

165

1.3 x 10-11

H+

p

150

8.0 x 10-12

H+

p

150

5.5 x 10-13

H+

p

145

6.0 x 10-13

H+

p

120

2.5 x 10-12

Ho

n

120

4.0 x 10-14

continued

 

 

Table 24 (continued)

Diffusivity of Various H Species in n-Type and p-Type Si

Species

Type

Temperature (C)

D (cm2/s)

Ho

n

150

3.6 x 10-13

H-

n

150

4.0 x 10-12

H-

n

120

7.5 x 10-13

H-

n

120

1.0 x 10-13

H-

n

120

5.0 x 10-15