Dipole Mode of Minority Carrier Diffusion with Reference to Point Contact Rectification

Abstract

The dipole mode of minority carrier diffusion about a spherical emitter is presented. The current‐voltage relationship, and frequency characteristics of this mode are determined. Compared with the unipole mode, which has been treated extensively, the dipole mode offers superior high‐frequency performance, which is partially offset by an inferior dc characteristic curve. A representative numerical example gives 40 mμsec mean response time with the unipole mode and 0.5 mμsec with the dipole mode. It is proposed that the reproducibility of special diode characterictics might be improved by designing diodes to suppress either the unipole or dipole mode. Methods are suggested for the suppression of either mode.