Time-dependent characteristics of titanium-silicide contacts to 6H-silicon carbide

Abstract

The processing conditions necessary to achieve low resistivity of the C54-TiSi 2 phase in contact with 6H-SiC are explored. This study demonstrates that an interlayer of Si between a Ti layer and the 6H-SiC substrate suppresses the formation of TiC, and that a metallization consisting of either Ti-rich or Si-rich silicide phases may be chosen. When the Ti-to-Si layer thickness ratio is 1:3, the C54-TiSi 2 and TiSi phases are observed following a 600°C/30 min and an 850°C/30 min annealing cycle. When the Ti-to-Si layer thickness ratio is 1:1, Ti 5 Si 3 and TiSi phases are observed following the same annealing cycle. Timedependent, in-situ resistance measurements are rationalized in terms of these microstructural developments. The Ti 5 Si 3 /TiSi structure is demonstrated to have a resistivity of 239 ⍀иcm, whereas the TiSi 2 /TiSi structure has a resistivity of only 23 ⍀иcm. Explanations for different microstructures observed are presented.

Electrically Conductive Silicon Carbide without Oxide Sintering Additives

“…It can be assumed that the electrical conductivity of SiC composite is mainly improved by the crystalline silicides and carbides of niobium and titanium which exhibit metallic conductivity. 19) The significant increase of electrical conductivity in our case is partly inhibited also by the presence of pores. The lower electrical conductivity of the sample SiCN30 (22.9 × 10 3 S•m −1 ) is mainly caused by the high porosity and low content of conductive phases, which probably do not form a continuous conductive network in the sample.…”