Growth Kinetics and Silicon Diffusivity in MoSi_2 and WSi_2 Disilicides

摘要

In the work experimental results on kinetics of silicide layers diffusive growth are presented at tungsten and molybdenum siliconizing in the medium of rarefied silane and silicon diffusion in WSi_2 and MoSi_2 phases at T = 850-1500 ℃ is studied. It is established that under the conditions considered a single-layer diffusive zone consisting of tungsten disilicide is formed on tungsten. On the molybdenum, alongside with MoSi_2 a Mo_5Si_3 layer is observed, however its thickness was approximately 10 times less than that of MoSi_2 layer and does not vary considerably during the process. Based on experimentally determined parabolic growth constants silicon diffusion coefficients in the WSi_2 and MoSi_2 phases are determined. For their temperature dependences the following expressions are derived: D_(WSi2)~(Si) = 4.96·10~(-2) exp(-38000 ± 2500/RT), cm~2/s D_(MoSi2)~(Si) = 2.46·10~(-2) exp(-35000 ± 2500/RT), cm~2/s.