<p>The exceptional radiation tolerance of silicon carbide (SiC) makes it as a critical material for next-generation devices operating in harsh radiative environments. However, the underlying mechanisms governing the evolution of neutron-induced defects and their correlation with electrical property degradation remain insufficiently understood. This study employs an integrated multiscale computational framework—combining binary collision approximation (BCA) approximate Monte Carlo simulation, molecular dynamics (MD), and kinetic Monte Carlo (KMC) simulations, supplemented with deep-level transient spectroscopy (DLTS)—to investigate the origin and dynamic evolution of defects in neutron-irradiated 4H-SiC material. MD simulations reveal ultrafast defect generation and recombination dynamics occurring on picosecond timescales, with carbon defects (<InlineEquation ID="IEq1"> <EquationSource Format="TEX">$V_{C}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>V</mi> <mi>C</mi> </msub> </math></EquationSource> </InlineEquation> and <InlineEquation ID="IEq2"> <EquationSource Format="TEX">$C_{I}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>C</mi> <mi>I</mi> </msub> </math></EquationSource> </InlineEquation>) dominating the early-stage damage due to the lower displacement threshold energy of carbon atoms. In contrast, silicon defects (<InlineEquation ID="IEq3"> <EquationSource Format="TEX">$V_{Si}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>V</mi> <mrow> <mi mathvariant="italic">Si</mi> </mrow> </msub> </math></EquationSource> </InlineEquation> and <InlineEquation ID="IEq4"> <EquationSource Format="TEX">$Si_{I}$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>S</mi> <msub> <mi>i</mi> <mi>I</mi> </msub> </mrow> </math></EquationSource> </InlineEquation>) exhibit more rapid recombination behavior. Extended KMC simulations demonstrate that <InlineEquation ID="IEq5"> <EquationSource Format="TEX">$C_{I}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>C</mi> <mi>I</mi> </msub> </math></EquationSource> </InlineEquation> is almost entirely annihilated through recombination and clustering processes, leading to the formation of stable complexes such as dicarbon interstitials (<InlineEquation ID="IEq6"> <EquationSource Format="TEX">$C_{I}C_{I}$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msub> <mi>C</mi> <mi>I</mi> </msub> <msub> <mi>C</mi> <mi>I</mi> </msub> </mrow> </math></EquationSource> </InlineEquation>) and carbon antisite–interstitial pairs (<InlineEquation ID="IEq7"> <EquationSource Format="TEX">$C_{Si}C_{I}$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msub> <mi>C</mi> <mrow> <mi mathvariant="italic">Si</mi> </mrow> </msub> <msub> <mi>C</mi> <mi>I</mi> </msub> </mrow> </math></EquationSource> </InlineEquation>). Conversely, <InlineEquation ID="IEq8"> <EquationSource Format="TEX">$V_{C}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>V</mi> <mi>C</mi> </msub> </math></EquationSource> </InlineEquation> persists as the most stable defect. DLTS characterization identifies several deep-level traps in the irradiated 4H-SiC material in the junction barrier Schottky diodes (JBS), which are closely related to the defects observed in multiscale evolution. Based on the qualitative correlation between simulation and experiment, these defects are proposed as likely major recombination centers which are responsible for significant carrier lifetime degradation. This study provides new insights into the defect evolution pathways in irradiated SiC across atomic and microscopic scales, establishes a critical structure–property relationship, and underscores the necessity of controlling vacancy-type defects for the design of radiation-resistant devices.</p>

Evolution and mechanism of neutron radiation defects in SiC materials based on multiscale simulation

期刊论文
发表日期：

2026年7月22日

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Qi Hu,
Fang Liu,
Heyi Li,
Cen Xiong,
Hang Zang,
Hongchao Zhao,
Binghuang Duan

摘要

The exceptional radiation tolerance of silicon carbide (SiC) makes it as a critical material for next-generation devices operating in harsh radiative environments. However, the underlying mechanisms governing the evolution of neutron-induced defects and their correlation with electrical property degradation remain insufficiently understood. This study employs an integrated multiscale computational framework—combining binary collision approximation (BCA) approximate Monte Carlo simulation, molecular dynamics (MD), and kinetic Monte Carlo (KMC) simulations, supplemented with deep-level transient spectroscopy (DLTS)—to investigate the origin and dynamic evolution of defects in neutron-irradiated 4H-SiC material. MD simulations reveal ultrafast defect generation and recombination dynamics occurring on picosecond timescales, with carbon defects ( $V_{C}$ $V_{C}$ and $C_{I}$ $C_{I}$ ) dominating the early-stage damage due to the lower displacement threshold energy of carbon atoms. In contrast, silicon defects ( $V_{Si}$ $V_{Si}$ and $Si_{I}$ $S i_{I}$ ) exhibit more rapid recombination behavior. Extended KMC simulations demonstrate that $C_{I}$ $C_{I}$ is almost entirely annihilated through recombination and clustering processes, leading to the formation of stable complexes such as dicarbon interstitials ( $C_{I}C_{I}$ $C_{I} C_{I}$ ) and carbon antisite–interstitial pairs ( $C_{Si}C_{I}$ $C_{Si} C_{I}$ ). Conversely, $V_{C}$ $V_{C}$ persists as the most stable defect. DLTS characterization identifies several deep-level traps in the irradiated 4H-SiC material in the junction barrier Schottky diodes (JBS), which are closely related to the defects observed in multiscale evolution. Based on the qualitative correlation between simulation and experiment, these defects are proposed as likely major recombination centers which are responsible for significant carrier lifetime degradation. This study provides new insights into the defect evolution pathways in irradiated SiC across atomic and microscopic scales, establishes a critical structure–property relationship, and underscores the necessity of controlling vacancy-type defects for the design of radiation-resistant devices.