Dependence of the incorporated boron concentration near SiO2/4H–SiC interface on trap passivation reduction

Abstract

By systematically varying the boron concentration near the oxide/4H–SiC interface within a specifically designed boron-diffusion layer oxide structure, this paper explores the influence of boron concentration on interface state density and near-interface trap density in 4H–SiC MOS capacitors. Additionally, the effect of boron near the oxide/4H–SiC interface on device stability under elevated temperature conditions was examined. The boron species were introduced into the SiO2/4H–SiC interface by spin coating followed by annealing, whose temperature controls the amount of boron present in the near interface region. It is suggested that a higher concentration of boron leads to a better trap passivation effect while preserving the stability of flat band voltage.

Investigating the mechanism of SiO2/4H-SiC interface traps passivation by boron incorporation through FT-IR analysis of near-interface SiO2

“…This coincides with the report that a higher B conc leads to a more pronounced NIT passivation. 5) We observed a reduction of over 50% in oxygen deficiency (δ from 0.41 to 0.23) from ThermSiO 2 to low B conc sample (BDL1050), accompanied by an order of magnitude drop in NIT density from 1´10 11 to 2´10 10 cm −2 . 5) This trend suggests that Bincorp likely passivates NIT by reducing oxygen deficiency near the interface.…”

“…Alkaline Earth elements (Sr, Ba) and phosphorus (P) have shown improved μ FE , surpassing that of nitridation annealing with NO. [2][3][4] Similarly, boron incorporation (B-incorp) improves μ FE by passivating the near interface traps (NIT) 5) and interface traps. 6) However, the mechanism behind B-incorp's passivation effect remains unclear.…”