Parametric description of the effect of electron irradiation on recombination lifetime in silicon layers: an experimental approach

Abstract

The aim of this paper is to perform an experimental investigation on the effects of electron beam irradiation on the recombination lifetime of both p-type and n-type silicon layers in order to provide a set of parameters useful to model the recombination effects in semiconductor computer simulation package. To this goal, we propose to use a proper three-terminal test structure in order to extract these parameters directly from lifetime measurements along the silicon layers at different temperatures and at different injection levels by using the same silicon samples before and after the electron irradiation process in order to highlight the effects of the irradiation itself on the lifetime.The experimental results indicate that the electron irradiation is more effective for controlling the high-injection lifetime in ptype silicon than in an n-type one. The effect of the irradiation on lifetime can be basically taken into account by means of one energy level placed at 0.27 eV below the conduction band edge for both n-type and p-type material, with p = = = 10 n.

Lifetime profile reconstruction in helium implanted silicon for planar IGBTs

“…The tailoring of those properties is usually performed by means of some form of lifetime engineering process [1,2]. Recombination lifetime, in fact, affects both switching speed and bulk resistivity [3], its value, in indirect gap semiconductors like silicon, depends on lattice defects which create allowed energy levels inside the bandgap; experimentally it is found that low doped silicon exhibits higher lifetimes than heavily doped one.…”

“…In the past years two special techniques, based on the operation of a three terminal test structure have been proposed to reconstruct the lifetime profile resulting from an ion implantation process. The first one is a modified OCVD scheme [6] while the second one is the differential technique [7]; the latter, in particular has already evidenced its reliability in numerous applications [1][2][3].…”