Modeling of the transient enhanced diffusion of boron implanted into preamorphized silicon

Abstract

We present a physically based modeling of the transient enhanced diffusion (TED) of boron implanted into preamorphized silicon. We start by describing the nucleation and growth of a supersaturation of Si interstitial atoms into dislocation loops. Our modeling of the nucleation and growth of the dislocation loops is divided into three distinct stages: the nucleation, the “pure growth,” and the Ostwald ripening. The implementation of this modeling into the process simulator IMPACT-4 allows one to correctly predict the size and density evolutions of the dislocation loops observed by transmission electron microscopy for a variety of annealing times and temperatures. This simulation also gives access to the concomitant behavior of the free Si interstitials atoms responsible for TED. Implementation of this model into IMPACT-4 shows that TED in preamorphized Si can be simulated for a variety of experimental conditions by assuming boron diffusion occurs through the coupling of boron atoms with this fast evolving supersaturation. It is shown that while not affecting too much the defect evolution itself, the value of the recombination velocity at the surface is a crucial parameter to correctly estimate the amount of TED after a given annealing. Best fits are obtained for recombination lengths of about 16 nm for annealing under Ar gas.