Multi-layers were investigated by using an in situ low-angle X-ray diffraction technique (table 1). The temperature-dependent interdiffusivities could be described by Arrhenius relationships (figure 1). It was concluded that the extremely small values of the pre-exponential factor (table 2), and a clear correlation between the pre-exponential factor and the activation energy for interdiffusion suggested that a collective jump mechanism which involved between 8 and 15 atoms governed interdiffusion in the monolayers.

Collective Interdiffusion in Compositionally Modulated Multilayers. W.H.Wang, H.Y.Bai, W.K.Wang: Journal of Applied Physics, 1999, 86[8], 4262-6

 

Table 1

Interdiffusivity between Monolayers at 458K

 

System

D (m2/s)

Ag/Bi

2.0 x 10-23

Ag/Si

8.22 x 10-24

Fe/Mo

4.1 x 10-25

Fe/Ti

1.75 x 10-24

Mo/Si

5.2 x 10-25

Nb-Si

2.68 x 10-24

Ni/Si

4.12 x 10-24

 

Table 2

Arrhenius Parameters for Interdiffusion between Monolayers

 

System

Do (m2/s)

E (eV)

Ag/Bi

4.30 x 10-21

0.21

Ag/Si

2.02 x 10-20

0.24

Fe/Mo

2.13 x 10-21

0.33

Fe/Ti

l.50 x 10-22

0.29

Mo/Si

6.20 x 10-21

0.37

Nb/Si

2.20 x 10-18

0.55

Ni/Si

2.13 x 10-17

0.69

 

Figure 1

Interdiffusivity of Monolayers