Nondestructive measurements of depth distribution of carrier lifetimes in 4H–SiC thick epitaxial layers using time-resolved free carrier absorption with intersectional lights

2023

Jpn. J. Appl. Phys.

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The on-resistance of bipolar devices depends on the carrier lifetime determined by Shockley-Read-Hall, surface, radiation and Auger recombination processes. Values for the Auger recombination coefficient have been previously reported, but the values were constant in each report. However, the Auger recombination coefficient should have dependence on the excited carrier concentration and presence of the traps. In this study, we observed excited carrier recombination in 4H-SiC under the high injection condition by time resolved free carrier absorption measurements. As a result, we found dependence on the excited carrier concentration of the Auger recombination coefficient and negligible effects of the traps on the coefficient.

Section: Experimental Methodsmentioning

confidence: 99%

4H-SiC Auger recombination coefficient under the high injection condition

Tanaka

Nagaya

2023

Jpn. J. Appl. Phys.

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“…Therefore, a remaining issue for bipolar degradation is the expansion of BPDs in substrates 25 – 27 . Inserting a “recombination enhancing layer” between a drift layer and a substrate has been suggested as an effective method to suppress the expansion of BPDs in the substrate 28 – 31 . This layer enhances the recombination probability of electron–hole pairs in the epitaxial layer and decreases the number of electron–hole pairs at the BPDs in the SiC substrate.…”

Section: Introductionmentioning

confidence: 99%

Suppression of stacking-fault expansion in 4H-SiC PiN diodes using proton implantation to solve bipolar degradation

Watanabe

Mii

et al. 2022

Sci Rep

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Abstract4H-SiC has been commercialized as a material for power semiconductor devices. However, the long-term reliability of 4H-SiC devices is a barrier to their widespread application, and the most important reliability issue in 4H-SiC devices is bipolar degradation. This degradation is caused by the expansion of single Shockley stacking-faults (1SSFs) from basal plane dislocations in the 4H-SiC crystal. Here, we present a method for suppressing the 1SSF expansion by proton implantation on a 4H-SiC epitaxial wafer. PiN diodes fabricated on a proton-implanted wafer show current–voltage characteristics similar to those of PiN diodes without proton implantation. In contrast, the expansion of 1SSFs is effectively suppressed in PiN diodes with proton implantation. Therefore, proton implantation into 4H-SiC epitaxial wafers is an effective method for suppressing bipolar degradation in 4H-SiC power-semiconductor devices while maintaining device performance. This result contributes to the development of highly reliable 4H-SiC devices.

“…[25][26][27] Inserting a "recombination enhancing layer" between a drift layer and a substrate has been suggested as an effective method to suppress the expansion of BPDs in the substrate. [28][29][30][31] This layer enhances the recombination probability of electronhole pairs in the epitaxial layer and decreases the number of electron-hole pairs at the BPDs in the SiC substrate. The reduction of electron-hole pairs decreases the driving force of REDG for BPDs in the substrate, and thus the recombination enhancing layer can suppress bipolar degradation.…”

Section: Introductionmentioning

confidence: 99%

Suppression of stacking-fault expansion in 4H-SiC PiN diodes using proton implantation to solve bipolar degradation

Watanabe

Mii

et al. 2022

Preprint

Self Cite

4H-SiC has been commercialized as a material for power semiconductor devices. However, the long-term reliability of 4H-SiC devices is a barrier to their widespread application, and the most important reliability issue in 4H-SiC devices is bipolar degradation. This degradation is caused by the expansion of single Shockley stacking faults (1SSFs) from basal plane dislocations in the 4H-SiC crystal. Here, we present a method for suppressing the 1SSF expansion by proton implantation on a 4H-SiC epitaxial wafer. PiN diodes fabricated on a proton-implanted wafer show current–voltage characteristics similar to those of PiN diodes without proton implantation. In contrast, the expansion of 1SSFs is effectively suppressed in PiN diodes with proton implantation. Therefore, proton implantation into 4H-SiC epitaxial wafers is an effective method for suppressing bipolar degradation in 4H-SiC power-semiconductor devices while maintaining device performance. This result contributes to the development of highly reliable 4H-SiC devices.