Relaxation of Current Flowing through Oxide Thermally Grown on Polycrystalline Silicon^†

Relaxation of the current flowing through an oxide thermally grown on polycrystalline silicon is studied in the spread time region (10⁻⁵ to 10³ s) and for the structures of the different area size (8 × 10⁻⁸ to 10⁻⁴ cm²). It is shown that the current relaxation curves cannot be approximated by the simple power law j ∽ t⁻ⁿ, with n < 1, as generally accepted, but having a complicated form with parts of constant current level and parts of current relaxation with the hyperbolic law j ∽ 1/t. A strong dependence of the form of the relaxation curves on the area size of the structure is observed. A model explaining the results by summing up the local currents is proposed. The area from which the current flows in the initial part of the relaxation curve is estimated.