Copper versus aluminum contacts for silicon devices

Aluminum (AI, PtSi-AI, PtSi-TiW-AICuSi) and copper (TiW-Ni-Cu, PtSi-TiW-NiCu) based contact stacks for high-power devices are compared using the measured forward I-V curves of P-i-N diodes. PtSi layer on silicon surface is found necessary to obtain low overall contact resistance and voltage drop of the device in the ON-state. The diodes with top layer from copper show lower overall contact resistance and better mechanical stability compared to that of aluminum