METAL-INDUCED GAP STATES MODEL OF NONIDEAL AU SI SCHOTTKY-BARRIER WITH LOW DEFECT DENSITY/

Temperature dependence of current-voltage characteristics was investig ated on Au/n-Si Schottky barrier. The experimental current density can be represented by a modified equation of the thermionic emission, in which nearly the same ideality factors n(Phi) and n(v) appear in the t emperature dependent exponential term of the barrier height Phi(B) and in that of the applied voltage V, respectively. Origin of n(Phi) is c onsidered to be spatially inhomogeneous Schottky barrier height distri bution. Origin of n(Phi) is considered to be applied bias dependence o f the effective barrier height. A microscopic model of the inhomogenei ty based on the MIGS model is proposed. Positively charged defects clo se to interface but outside the evanescent tail of MIGS produce local lowering of barrier height due to induced charge density, which depend s on a distance of the defect from interface. The local barrier height lowering is restored by disappearance of the defect charge under forw ard bias. This model is applicable to interfaces of defect density low er than 10(14) cm(-2), which has been considered to be necessary for t he Fermi level pinning. (C) 1998 Elsevier Science B.V. All rights rese rved.