Determination of ohmic contacts to n-type 6H- and polycrystalline 3C-SiC using circular transmission line structures

Abstract Ohmic contacts to n-type 3C- and 6H-SiC were investigated using the circular transmission line method (CTLM). For the contact metallization titanium-tungsten, tungsten and tungsten disilicide were used. The determination of the specific contact resistance using two different test structures of CTLMs was tried, but it was shown that the end contact measurements as they were proposed in the more sophisticated model by Reeves were too high and the equations were not solvable within the conditions of the present study. The specific contact resistance was calculated by the method of Marlow and Das. Annealing the contacts resulted for TiW contacts in a ϱc=3.7 × 10−4 ω cm−2 to 6H-SiC (7.1 × 10−5 ω cm−2 to 3C-SiC) and for WSi2 contacts in a ϱc=2.1 × 10−5 ω cm−2 to 6H-SiC (2.20 × 10−5 ω cm−2 to 3C-SiC).