A unified model for insulator selection to form ultra-low resistivity metal-insulator-semiconductor contacts to n-Si, n-Ge, and n-InGaAs

A comprehensive, physics-based unified model is developed for study of low resistivity metal-insulator-semiconductor (M-I-S) ohmic contact. Reduction in metal-induced gap state density and Fermi unpinning in semiconductor as a function of insulator thickness is coupled with electron transport including tunnel resistance through the metal-insulator-semiconductor (M-I-S) system to calculate specific contact resistivity at each insulator thickness for n-Si, n-Ge, and n-InGaAs. Low conduction band offset results in similar to 1 x 10(-9) Omega-cm(2) contact resistivity with TiO2 insulator on n-Si, similar to 7 x 10(-9) Omega-cm2 can be achieved using TiO2 and ZnO on n-Ge, and similar to 6 x 10(-9) Omega-cm(2) can be achieved with CdO insulator on n-InGaAs, which meet the sub-22nm CMOS requirements. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4739784]