An experimental verification of the electrostatic field gradient theory for diffused semiconductors

Abstract

The process of diffusion leads to a deterioration in the minority carrier lifetime. It has been suggested that the gradation of impurity atoms, leads to an electrostatic field as well as an electrostatic field gradient in the diffused semiconductor. From the continuity equations for minority carriers in the diffused region, it has been deduced that the field gradient term acts as a virtual recombination term for the minority carriers. The experimental verification of this theory on a qualitative basis has been achieved by measuring the resistivity and lifetime on a diffused sample at different depths along the diffusion profile. From the interpretation of the results given here it has been concluded that the field gradient theory is tenable and gives a realistic picture of the situation in contrast to some other theories proposed before.