Dual-Sublattice Modeling and Semi-Atomistic Simulation of Boron Diffusion in 4H-Silicon Carbide

Abstract

Reported profiles of high-temperature (500 C)-implanted boron ions diffused in 4H-silicon carbide at 1200 -1900 C for 5 -90 min were simulated through a ''dual-sublattice'' modeling, in which a different diffusivity is assigned for diffusion via each sublattice, and a ''semiatomistic'' simulation, in which silicon and carbon interstitials are regarded as the same interstitials (I) and silicon and carbon vacancies are regarded as the same vacancies (V). Diffusion of implanted boron ions is calculated from the initial concentration profiles of I and V by Monte-Carlo simulation assuming tentatively a probability of 50% that implanted boron ions will occupy carbon sublattices.

Influence of Defects on Low Temperature Diffusion of Boron in SiC

“…In our previous work [4], based on an analysis of literature on diffusion mechanisms in SiC [7][8][9][10][11] has been assumed that the accelerated diffusion takes place via mobile (B c -V c ) associates. However, according to expressions (2,3) silicon vacancy are also formed on the surface of the crystal.…”

One-Dimensional Models for Diffusion and Segregation of Boron and Ion Implantation of Aluminum in 4H-Silicon Carbide

“…The diffusion of B C (Bockstedte et al, 2003) is modeled next. Since B C can be regarded as an acceptor (Mochizuki et al, 2009)…”

“…A "dual-sublattice" diffusion modeling, in which a different diffusivity is assigned for diffusion via each sublattice, was proposed next. At the same time, a "semi-atomistic" simulation, in which silicon interstitials (I Si ) and carbon interstitials (I C ) are approximated as the same interstitials (I) and silicon vacancies (V Si ) and carbon vacancies (V C ) are approximated as the same vacancies (V), was performed (Mochizuki et al, 2009). Although this approximation originally comes from the limitation of a commercial process simulator, it contributes to reducing the number of parameters needed in an atomistic simulation using a continuity equation of coupling reactions between I Si , I C , V Si , V C , and diffusing species.…”

Modeling of Boron Diffusion and Segregation in Poly-Si/4H-SiC Structures

“…In regard to 4H-SiC, boron diffusion above 1300 °C has been modeled with a double-negatively charged boron-silicon interstitial (I Si ) pair and a single-positively charged boron-carbon interstitial (I C ) pair [6]. However, the present study only took into account the latter pair diffusivity because extrapolation of the former pair diffusivity to less than 1000 °C results in quite small values (Fig.…”