A SEM-EBIC minority-carrier lifetime-measurement technique

Abstract

A SEM-EBIC minority-carrier lifetime-measurement method is described, whereby an arrangement is used such that the electron beam is incident normal to the charge-collecting barrier; the barrier may be either that of a Schottky diode or of a very shallow p-n junction. The beam is positioned at a constant point over the barrier, and the lifetime is found by rapidly switching off the beam and analysing the resulting EBIC time decay. In many practical cases this decay is given by I(t) varies as (exp(-t/ tau ))/t^1/2 where tau is the lifetime and I(t) the EBIC at time t after the beam is switched off, and therefore plotting ln(It^1/2) versus t results in a straight line from the slope of which tau can be obtained.