Modeling of Al Doping During 4H-SiC Chemical-Vapor-Deposition Trench Filling

Abstract

Aluminum doping during 4H-SiC chemical-vapor-deposition (CVD) trench filling was numerically modeled toward precise design of high-voltage superjunction devices. As a first-order approximation, growth-rate-and surface-normal-scaling functions were determined based on the reported experimental results. Simulated isoconcentration contours of aluminum were confirmed to qualitatively agree with the reported imaging of doping in SiC by scanning spreading resistance microscopy. Improvement of the proposed models based on additional experiments should contribute to reducing the development time for 4H-SiC superjunction devices fabricated using CVD trench filling. INDEX TERMS Aluminum, power semiconductor devices, silicon compounds, simulation.

Estimation of surface-diffusion length of aluminum-containing species on 4H-SiC (0001)

“…15) This quasi-thermodynamic model has also been used to quantitatively analyze aluminum doping during trench-filling epitaxial growth of 4H-SiC. 16,19) The maximum x analyzed in this study is 5.8 × 10 -5 , 20) which is much less than 0.01. 15) Accordingly, the same model is employed to quantitatively analyze the reported x in Al x Si 1-x C on misoriented (0001) substrates.…”

“…Under this condition, aluminum segregation can be observed because segregation coefficient is less than unity. 16,19) An impurity can segregate not only at the surface site, 25) but also at the step-edge 26,27) and kink 28,29) sites. According to Yamamoto et al, 20) the aluminum concentration in 4H-SiC (0001̅ ) decreased with increasing θ.…”