High-temperature contact metallization to semiconductors

Contacts are the limiting factor in the performance of electronic devices operated at high temperatures. To fulfil the advanced requirements for contacts in that application, the most effective metallization scheme, at present, is one which is functionally divided into intermediate layers. A diffusion barrier is introduced between the interconnecting metal and the semiconductor to minimize interactions between the two. The best results are obtained with chemically inert ternary amorphous alloys that lack extended defects and grain boundaries. The contacting layer determines the electrical characteristics of the contact. Its design is complicated by the complex multielemental nature of its chemical interaction with high-temperature compound semiconductors. The concept and implementation of diffusion barriers and contacting layers are discussed with an emphasis on contacting layers to SiC.