Observation of carrier lifetime distribution in 4H-SiC thick epilayers using microscopic time-resolved free carrier absorption system

Nagaya, Keisuke; Hirayama, Takashi; Tawara, Takehiko; Murata, Koichi; Tsuchida, Hidekazu; Miyasaka, Akira; Kojima, Kazutoshi; Kato, Tomohisa; Okumura, Hajime; Kato, Masashi

doi:10.1063/5.0015199

Cited by 7 publications

(6 citation statements)

References 42 publications

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“…We used a 355 nm pulsed yttrium aluminum garnet (YAG) laser (injected photons: ∼10 17 cm −2 , pulse width: 1 ns) as the excitation light, and a continuous wave laser (wavelength: 637 nm) as a probe light. 25) Both lasers were focused by the objective lens with an NA of 0.65 (PAL-50-NUV-HR-L, SHIGMAKOKI Co. Ltd.). Then, the spot diameter of the excitation light and probe light was approximately 100 μm and 1 μm, respectively, and this condition was corresponding to the expanded measurement mode in Ref.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…For carrier lifetime measurements of SiC, there are three typical contactless techniques: microwave photoconductivity decay, time-resolved photoluminescence, and time-resolved free carrier absorption (FCA) methods. [22][23][24][25] Given that the typical thickness of epitaxial layers and scale of the SJ structures are in the range of 1-30 μm, spatial resolution in measurements is important. Among the measurement techniques, the FCA method leads to the highest spatial resolution.…”

Section: Introductionmentioning

confidence: 99%

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Effects of ion implantation process on defect distribution in SiC SJ-MOSFET

Fukui¹,

Ishii²,

Tawara³

et al. 2023

Jpn. J. Appl. Phys.

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A superjunction (SJ) structure in power devices is compatible with low specific on-resistance and high breakdown voltage. To fabricate the SJ structure in SiC power devices, the repetition of ion implantation and epitaxial growth processes is a practical method. However, the impact of ion implantation on device performance has rarely been reported. In this study, we measured the carrier lifetime distributions in a SiC MOSFET with an SJ structure using a microscopic free carrier absorption method. Furthermore, we observed the distribution of defects via cathodoluminescence and deep levels via deep-level transient spectroscopy. We observed that Al ion implantation induced defects and reduced the carrier lifetime in the SJ structure. However, N ion implantation does not significantly induce defects. Additionally, Al ion implantation at room temperature exhibited more significant effects than implantation at 500°C. The results can aid in controlling the carrier lifetime in SiC SJ MOSFETs.

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Section: Experimental Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effects of ion implantation process on defect distribution in SiC SJ-MOSFET

Fukui¹,

Ishii²,

Tawara³

et al. 2023

Jpn. J. Appl. Phys.

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“…For carrier lifetime measurements, a third harmonic yttrium aluminum garnet laser with a wavelength of 355 nm and a pulse width of 1 ns was used as the excitation light source. A continuous-wave laser with a wavelength of 637 nm was used as the probe light, and micro-time-resolved free carrier absorption (FCA), [24][25][26][27] which constitutes an objective lens, was used.…”

Section: Experimental Methodsmentioning

confidence: 99%

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

Tanaka

Nagaya

Kato

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.

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“…[ 9 ] It should be mentioned in this regard that carrier lifetime control in such optically thick epilayers has already gained considerable attention worldwide. [ 10–18 ]…”

Section: Introductionmentioning

confidence: 99%

“…[9] It should be mentioned in this regard that carrier lifetime control in such optically thick epilayers has already gained considerable attention worldwide. [10][11][12][13][14][15][16][17][18] Accordingly, the material of choice for the thermal generation and C-injection experiments should preferably involve ultra-thick and low-doped epilayers to ensure a broader profiling range and depth discrimination.…”

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confidence: 99%

Cross‐Sectional Carrier Lifetime Profiling and Deep Level Monitoring in Silicon Carbide Films Exhibiting Variable Carbon Vacancy Concentrations

Galeckas

Karsthof

Gana

et al. 2022

Physica Status Solidi (a)

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Silicon carbide (SiC) is a wide bandgap semiconductor with material properties allowing for electronic applications operating under harsh conditions, such as high temperature and radiation.Among the key challenges yet to be resolved is mastering and control of the electrically active point defects, particularly in the technologically most relevant 4H-SiC polytype. The point defects spontaneously generated in a radiation-hard environment usually shorten the carrier lifetime degrading the performance of power electronics and radiation sensors. In contrast, the irradiation by swift ions, e.g., by MeV protons, can be used as a tool for the controlled introduction of radiation-defect-related recombination centers for optimizing lifetime and dynamic characteristics. [1] Still, the longest possible minority carrier lifetime in 4H-SiC epitaxial layers is the key prerequisite for the realization of high-voltage bipolar power devices; e.g., to modulate carrier conductivity in the voltage-blocking layer of a 10 kV class device comprised of 100 μm thick epilayer with doping concentration %10 15 cm À3 , the required carrier lifetime is in the range of 10 μs. In recent years, carrier lifetimes in excess of several microseconds are being demonstrated after the origin of inherently short (sub-microsecond) lifetimes has been associated with intrinsic point defect, carbon vacancy (V C ), acting as a lifetime killer. [2] In response, several remedies to diminish such defects have been developed, such as carbon implantation, high-temperature oxidation, and thermal equilibration in carbon-rich conditions. [3][4][5][6] In 4H-SiC, V C exhibits electrical

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Observation of carrier lifetime distribution in 4H-SiC thick epilayers using microscopic time-resolved free carrier absorption system

Cited by 7 publications

References 42 publications

Effects of ion implantation process on defect distribution in SiC SJ-MOSFET

Effects of ion implantation process on defect distribution in SiC SJ-MOSFET

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

Cross‐Sectional Carrier Lifetime Profiling and Deep Level Monitoring in Silicon Carbide Films Exhibiting Variable Carbon Vacancy Concentrations

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