Thermal stability of the Cu/Pd/Si metallurgy Available to Purchase

The reaction between Cu and Pd/Si is studied using Cu/Pd/Si structures between 200 and 600 °C. The structural analyses show the reaction between Cu and Pd/Si between 200 and 300 °C, with both Pd and Si diffusing into Cu, and Cu accumulating inside the Si region under the Pd₂ Si layer formed. An extensive reaction between Cu and Pd₂ Si is observed at 400 °C, forming Cu silicides and Cu₃ Pd. The instability of the Cu/Pd₂ Si metallurgy is comparable to those of Al/Pd₂ Si and Cu/PtSi. In this regard, the difference in stability between the Cu/Pd/Si and Cu/Pt/Si structures is much smaller than that between the Al/Pd/Si and Al/Pt/Si ones. For the latter structures, a difference of about 100 °C is observed, with or without common barrier layers, with Al/Pt/Si being the more stable one. The ready formation of both Cu silicides and Cu₃ Pd contributes to the instability of the Cu/Pd/Si structure. The Cu silicide reaction is also responsible for the low thermal stability of the Cu/Pt/Si structures.