Theoretical specific resistance of ohmic contacts to n-GaAs

An improved version of a prior model is given for specific resistance of ohmic contacts to n-GaAs. Instead of the two-band model used in the prior work for the transmission coefficient, a more rigorous three-band model due to E. O. Kane [J. Phys. Chem. Solids 1, 249 (1957)] is used in the improved version. In the doping range of interest, the theoretical contact resistance can differ by more than an order of magnitude, particularly at high intrinsic barrier heights. The contact resistance is given as a function of doping and the intrinsic barrier height. An ultimate limit to the contact resistance is also given.