Siliconizing of Molybdenum Metal in Indium-Silicon Melts
Siliconizing of Mo to form a silicide layer was investigated in the In–Si melt alloy with a two phase mixture of a solid Si and an In–Si melt at temperatures between 1273 and 1473 K for up to 90 ks in a vacuum ampoule. The MoSi<SUB>2</SUB> layer was grown in thick because an activity of silicon in the melt alloy is close to unity, accompanied by a formation of a thin Mo<SUB>5</SUB>Si<SUB>3</SUB> layer between the MoSi<SUB>2</SUB> layer and Mo substrate. These two layers grew in accordance with a parabolic rate raw.<BR>Chemical diffusion coefficients in both the MoSi<SUB>2</SUB> and Mo<SUB>5</SUB>Si<SUB>3</SUB> layers were obtained using Wagner analysis for the diffusion couple of a Mo/Mo<SUB>5</SUB>Si<SUB>3</SUB>/MoSi<SUB>2</SUB>/Si (in the melt). Activation energies for the growth rate constants are 157 kJ/mol for the MoSi<SUB>2</SUB> and 350 kJ/mol for the Mo<SUB>5</SUB>Si<SUB>3</SUB>, respectively, and they are the same as those for chemical diffusion coefficients due to the fact that terminal compositions of 37.5 and 39.1 at%Si for both sides of the Mo<SUB>5</SUB>Si<SUB>3</SUB> layers are almost independent of temperature. Composition of 39.1 at%Si was coincided with the measured one for the two MoSi<SUB>2</SUB>+Mo<SUB>5</SUB>Si<SUB>3</SUB> phase alloy, which was smaller than 40 at%Si cited in the phase diagram. Duplex layer structure and its growth kinetics in the present In–Si melt method were consistent with those obtained in the CVD method.
- Materials transactions, JIM
Materials transactions, JIM 39(6), 658-662, 1998-06