Theory of electrical characteristics of a Schottky barrier having exponentially distributed impurity states and metal-insulator-metal structures

The metal-insulator or metal-amorphous semiconductor blocking contact is still not well understood. Here, the author discusses the steady state characteristics of a non-intimate metal-insulator Schottky barrier. He considers an exponential distribution (in energy) of impurity states in addition to impurity states at a single energy level within the depletion region. He presents analytical expressions for the electrical potential, field, thickness of depletion region, capacitance, and charge accumulated in the depletion region. He also discusses ln I versus V ap data. Finally, he compares the characteristics in three cases: (i) impurity states at only a single energy level; (ii) uniform energy distribution of impurity states; and (iii) exponential energy distribution of impurity states. In general, the electrical characteristics of Schottky barriers and metal-insulator-metal structures with Schottky barriers depend strongly on the energy distribution of impurity states.