Low specific resistance (&amp;lt;6×10−6 Ω cm2) TiC ohmic contacts to <i>n</i>-type β-SiC

Abstract

An array of transfer length measurement (TLM) structures was formed on an electrically isolated n+β=SiC (111) epilayer. The n+β-SiC epilayer was in situ doped with a nitrogen concentration of 2×1019 cm−3. The specific contact resistance (pc), sheet resistance (Rs), contact resistance (Rc), and transfer length (LT) were calculated from resistance (RT) versus contact spacing (d) measurements obtained from 10 TLM structures. The linear curves used for these calculations were fit to the RT versus d data by calculating the standard error of linear regression of RT on d; where, the average correlation coefficient with a straight line was 1.0000 and the average standard error of linear regression of RT on d was 0.26 Ω. The resulting average values were: pc=5.4×10−6 Ω cm2, Rs=22 Ω/⧠, Rc=1.45 Ω, and LT=5.0 μm. The TiC contacts, epitaxially grown by chemical vapor deposition, could not be scratched with a tungsten carbide scriber, nor could they be delaminated from the β-SiC surface.