High temperature stable metallization schemes for SiC-technology operating in air

Complete metallization schemes for SiC based high temperature applications were investigated with regard to their physical and chemical stability, and their electrical behaviour under the influence of a high temperature air ambient. Two metal silicides, MoSi₂ and WSi₂, were used as contacts to the 6H-SiC substrate. MoSi ₂ and WSi₂ show ohmic behaviour after thermal contact formation. The specific contact resistances obtained are in the range from 10^-4 to 10^-5 Ω cm². To keep the system design simple for these investigations, both silicides were used for on-chip interconnects. The connection to the next wiring level was realized by an 3 μm Al cover layer and Al thick wire bonding. All systems show electrically stable behaviour during thermal storage at 400°C for more than 1000 hours. No intermixing or degradation within the systems was found by Auger electron spectroscopy depth profile analysis and electrical measurements