DETERMINATION OF OHMIC CONTACTS TO N-TYPE 6H-SIC AND POLYCRYSTALLINE 3C-SIC USING CIRCULAR TRANSMISSION-LINE STRUCTURES

Ohmic contacts to n-type 3C- and 6H-SiC were investigated using the ci rcular transmission line method (CTLM). For the contact metallization titanium-tungsten, tungsten and tungsten disilicide were used. The det ermination 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 co nditions of the present study. The specific contact resistance was cal culated by the method of Marlow and Das. Annealing the contacts result ed for TIW contacts in a rho(C) = 3.7 x 10(-4) Omega cm(-2) to 6H-SiC (7.1 x 10(-5) Omega cm(-2) to 3C-SiC) and for WSi2 contacts in a rho(C ) = 2.1 x 10(-5) Omega cm(-2) to 6H-SiC (2..20 x 10(-5) Omega cm(-2) t o 3C-SiC). (C) 1998 Elsevier Science S.A.