TRAP-LIMITED HYDROGEN DIFFUSION IN BORON-DOPED SILICON

The hydrogen diffusion process in boron-doped silicon for temperatures T in the range from 60-degrees-C to 140-degrees-C is entirely trap limited and shows no dependence on the diffusivity of the free hydrogen. The effective hydrogen diffusion coefficient D(eff) is determined at two values of the boron concentration N(A) = 1.4 x 10(15) cm-3 and N(A) = 3.8 x 10(16) cm-3. The values of D(eff) satisfy the Arrhenius equation N(A)D(eff) = P0exp(-E(p)/kT) with E(P) = 1.28 eV and P0 = 1 x 10(20) cm-1 s-1. We present a model which predicts that N(A)D(eff) = nu/(4-pi-R), where nu is the dissociation frequency of the BH complex and R congruent-to 3.5 nm the collision radius which describes the trapping of H at the boron atom.