Simulation of boron, phosphorus, and arsenic diffusion in silicon based on an integrated diffusion model, and the anomalous phosphorus diffusion mechanism

Abstract

Boron (B), phosphorus (P), and arsenic (As) in-diffusion profiles were simulated based on an integrated diffusion model that takes into account the vacancy mechanism, the kick-out mechanism and the Frank–Turnbull mechanism. The simulations were done using just three parameters for B and P, and four parameters for As, each of which has a clear physical meaning and a physically reasonable value, with no additional ad hoc hypothesis. These parameters correspond to the diffusion of dopant species and of point defects that contribute to dopant diffusion. For the anomalous P diffusion profile, the vacancy mechanism governs the diffusion in the plateau region, while the kick-out mechanism governs it in the deeper region, where self-interstitials dominate in the kink region and P interstitials dominate in the tail region. This changeover from the vacancy contribution to the kick-out contribution is shown to be the mechanism for the appearance of the kink-and-tail profiles of P. Moreover, the comparison among B, P, and As diffusion is made to review the diffusion of these three dopants by means of a unified model.

Simultaneous Phosphorus and Si Self-Diffusion in Extrinsic, Isotopically Controlled Silicon Heterostructures

“…Additionally, the P diffusivity was found to be proportional to the square of the P concentration for high P concentrations, indicating that the vacancy mechanism involving a doubly negatively charged vacancy (V -2 ) is the dominant diffusion mechanism at high P concentrations [11]. This work will provide insight into the native defects involved in the diffusion of P in Si as well as contributions of vacancies and selfinterstitials to Si self-diffusion, but also yields a more detailed insight into the mechanism of dopant diffusion compared to previous studies that were restricted to the analysis of dopant profiles alone [12].…”

“…Only every third SIMS data point is shown for clarity. The diffusion reactions proposed by Uematsu are inset [12].…”

“…The temperature dependences of the P diffusion coefficient and the I -contribution to selfdiffusion are given by the following expressions (both results refer to electronically intrinsic conditions): Figure 2 SIMS concentration profiles of 30 Si (circles) and 31 P (squares) for a sample annealed at 1100 °C for 30 minutes, along with simulations for the model proposed by Uematsu [12]. The dashed line represents best fit of Uematsu's model to the P profile, while the solid line is the best fit of Uematsu's model to the Si profile.…”

“…The model proposed by Uematsu, [12], is based on a kick-out mechanism of interstitial diffusion involving a neutral interstitial, I o , and a vacancy mechanism for vacancy mediated diffusion involving a singly and doubly negatively charged vacancy, V -and V -2 . In the model proposed in this work, no contribution from a vacancy mechanism is required and no evidence of the involvement of a doubly negatively charged native defect is observed, while a negatively charged interstitial is required along with a positively charged P species.…”

Fabrication and doping of silicon micropillar arrays for solar light harvesting

“…Atmospheric-pressure CVD [3,66,103] No Yes 100-3000 Yes Plasma-enhanced CVD [68,70,72] Yes Yes 100-3000 Yes…”