The diffusion of Cu through the grain boundaries of 500nm-thick ion-plated Ag-12at%Sn films was studied at 100 to 250C. The method was based upon determination of the moment at which Cu first appeared on the Ag-Sn surface. This was done by using Auger electron spectroscopy to determine trace amounts of Cu. It was found that the results (table 21) could be described by:

D (cm2/s) = 1.3 x 10-7 exp[-0.53(eV)/kT]

Studies of Cu diffusion through ion-plated pure Ag layers were also carried out. In this case, the results were described by:

D (cm2/s) = 2.3 x 10-5 exp[-0.68(eV)/kT]

A.Bukaluk, M.Rozwadowski, R.Siuda: Surface Science, 1988, 200, 381-5

 

Table 20

Diffusion of 110mAg in Ag-Sn

 

Sn (at%)

Temperature (K)

D (cm2/s)

0

618

8.35 x 10-17

0.80

618

1.97 x 10-16

1.25

618

2.76 x 10-16

1.80

618

3.84 x 10-16

Table 20 (continued)

Diffusion of 110mAg in Ag-Sn

 

Sn (at%)

Temperature (K)

D (cm2/s)

3.04

618

7.74 x 10-16

3.44

618

8.51 x 10-16

0

629

3.40 x 10-16

0.54

629

3.01 x 10-16

1.15

629

8.34 x 10-16

1.73

629

8.35 x 10-16

2.23

629

1.13 x 10-15

2.59

629

1.19 x 10-15

2.85

629

1.07 x 10-15

4.56

629

2.68 x 10-15

0

643

8.23 x 10-16

0.49

643

9.45 x 10-16

0.80

643

8.53 x 10-16

1.70

643

1.70 x 10-15

2.03

643

1.93 x 10-15

2.54

643

2.39 x 10-15

3.04

643

2.73 x 10-15

0

652

1.40 x 10-15

0.49

652

1.44 x 10-15

0.80

652

1.38 x 10-15

1.25

652

3.33 x 10-15

1.80

652

2.61 x 10-15

2.03

652

5.18 x 10-15

2.54

652

3.11 x 10-15

3.04

652

4.37 x 10-15

3.44

652

7.18 x 10-15

0

654

1.09 x 10-15

0.49

654

1.36 x 10-15

0.80

654

1.49 x 10-15

1.25

654

1.70 x 10-15

continued

Table 20 (continued)

Diffusion of 110mAg in Ag-Sn

 

Sn (at%)

Temperature (K)

D (cm2/s)

1.80

654

4.22 x 10-15

2.03

654

5.37 x 10-15

3.04

654

6.87 x 10-15

3.44

654

8.30 x 10-15

 

Table 21

Grain Boundary Diffusion

of Cu in Ag-12at%Sn Films

 

Temperature (K)

D (cm2/s)

493

4.1 x 10-13

461

2.5 x 10-13

426

5.6 x 10-14

373

1.0 x 10-14