Carrier transport through grain boundaries in semiconductors

Abstract

The transport of majority carriers through an electrically active grain boundary is treated for the situation where deep traps are an essential feature of the bulk semiconductor. Electrons trapped at the interface are screened by the ionized defect states within the depletion regions and thereby a double Schottky potential barrier is formed. The leakage and nonlinearity of the steady-state current across such a grain boundary depend strongly on the distribution of interface states and on the density of the available screening charge. The ac small-signal conductance and capacitance are governed by both the finite response time of the interface and the deep bulk traps. From measurements of the static and dynamic quantities it is then possible to determine the microscopic parameters of the grain boundary.