Side-Illuminated Photoconductive Semiconductor Switch Based on High Purity Semi-Insulating 4H-SiC

Choi, Pyeung Hwi; Kim, Yong Pyo; Kim, Min-Seong; Ryu, Jiheon; Baek, Seung-Hwan; Hong, Sun-Gi; Lee, Sungbae; Jang, Jae‐Hyung

doi:10.1109/ted.2021.3117535

Cited by 12 publications

(6 citation statements)

References 30 publications

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“…However, these devices did not use the C-doped layer that is central to the present high-speed operation. However, progress on the device fabrication side is being made [53,54]. Hence, it is likely that a true high-speed pulse compression GaN PCSS may be realized in the near future that is capable of operating in the 100 GHz regime as predicted here for a rugged and robust advanced high power PCSS alternative.…”

Section: Discussionmentioning

confidence: 89%

Density-Dependent Effects on Pulse Compression in GaN Photodetectors Probed by Monte Carlo Studies

2022

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With increases in the demand for faster electronic switching, requirements for higher operating voltages and currents, and the need to perform under harsh environments while operating at even higher frequencies, the research focus in photoconductive semiconductor switch (PCSS) technology has shifted to wide bandgap semiconductors. Here, we examine the possibility of pulse compression in carbon-doped PCSS devices based on the negative differential mobility concept for faster operation. Monte Carlo simulations are used to build in and model various effects on electron transport including degeneracy, charge polarization, and scattering within a three-valley model fitted to bandstructure calculations. The focus is on exploring the density dependence of pulse compression. Thresholds for the biasing fields naturally emerge. Predictive analysis of the output full-width half-maximum (FWHM) current waveforms, as well as the dynamics of the internal charge cloud behavior, and occupancy of the various valleys within GaN are all obtained. Our results show that an increase in carrier density can increase pulse compression and create pulse-widths that are smaller than the FWHM of the input optical excitation. This bodes well for enhanced repetition rates. Variations produced by moving the laser spot along the GaN PCSS length are also examined. Though data for GaN are not yet available, the trends compare well qualitatively with previous reports for GaAs.

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Section: Discussionmentioning

confidence: 89%

Density-Dependent Effects on Pulse Compression in GaN Photodetectors Probed by Monte Carlo Studies

2022

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“…1(a), 8-mm-diameter circular electrodes were formed on both sides of the 1.3×1.3 cm 2 substrate by optical lithography, where the photoresist (AZ5214) was utilized for image reversal process and a mask aligner (M100, PRO Win) was used for optical exposure and flood exposure. Subsequently, the multilayer metallization consisting of Ni/Ti/Au (40/40/300 nm) was evaporated and lifted-off [22]. As shown in Fig.…”

Section: Methodsmentioning

confidence: 99%

“…In this work, a side-illuminated vertical PCSS based on HPSI 4H-SiC was fabricated to investigate current switching capability. The side-illuminated vertical PCSS device exhibited high optical absorption efficiency so that a low onstate resistance can be achieved at low optical excitation energy [22]. A 532-nm laser was utilized for the optical coupling of the entire volume of the vertical PCSS.…”

Section: Introductionmentioning

confidence: 99%

Output Characteristics of Side-Illuminated Photoconductive Semiconductor Switch Based on High Purity Semi-Insulating 4H-SiC

Choi

Kim

et al. 2022

IEEE Access

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Photoconductive semiconductor switch (PCSS) allowing side illumination was fabricated on high purity semi-insulating (HPSI) 4H-SiC. A 532-nm pulsed laser with variable optical energy was used to trigger the PCSS. The performance of the PCSS was characterized under the two different load conditions, 50-Ω load and 0.05-Ω, with a current viewing resistor (CVR). The PCSS exhibited significantly different output characteristics for the two different loads. The equivalent resistance of the PCSS with the 50-Ω load, which was calculated from the output voltage and current, was inversely proportional to the optical energy, but the one with a 0.05-Ω load exhibited saturation behavior with the optical energy. While the times at peak output with the 50-Ω load were similar at various optical energies, the times at peak output with the 0.05-Ω load were dependent on the optical energy. Output current oscillation was also observed after the PCSS was turned off in the case of 0.05-Ω load condition. The different output characteristics for the different load resistances were analyzed using the transient response of the equivalent circuits. The PCSS exhibited a minimum on-state resistance of 0.27 Ω with the optical energy of 8 mJ and a maximum output current of 657 A at the bias voltage of 4.8 kV. The operating voltage of the PCSS was limited by surface flashover, which caused an additional output pulse following the first output pulse.

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“…As one can see, defects can deteriorate the device characteristics in many ways [91,117]. Although the negative effects of defects can be counteracted by designing different device structures [1][2][3][118][119][120][121][122][123], establishing a fast and accurate defect inspection system is amid a pressing need to help one observe defects and further optimize the process to reduce them. Note that analyzing the characteristics of SiC devices to identify type and the presence of defects could potentially be used as a defect inspection method (Figs.…”

Section: Impact Of Defects On Devicesmentioning

confidence: 99%

Defect Inspection Techniques in SiC

et al. 2022

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With the increasing demand of silicon carbide (SiC) power devices that outperform the silicon-based devices, high cost and low yield of SiC manufacturing process are the most urgent issues yet to be solved. It has been shown that the performance of SiC devices is largely influenced by the presence of so-called killer defects, formed during the process of crystal growth. In parallel to the improvement of the growth techniques for reducing defect density, a post-growth inspection technique capable of identifying and locating defects has become a crucial necessity of the manufacturing process. In this review article, we provide an outlook on SiC defect inspection technologies and the impact of defects on SiC devices. This review also discusses the potential solutions to improve the existing inspection technologies and approaches to reduce the defect density, which are beneficial to mass production of high-quality SiC devices.

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Side-Illuminated Photoconductive Semiconductor Switch Based on High Purity Semi-Insulating 4H-SiC

Cited by 12 publications

References 30 publications

Density-Dependent Effects on Pulse Compression in GaN Photodetectors Probed by Monte Carlo Studies

Density-Dependent Effects on Pulse Compression in GaN Photodetectors Probed by Monte Carlo Studies

Output Characteristics of Side-Illuminated Photoconductive Semiconductor Switch Based on High Purity Semi-Insulating 4H-SiC

Defect Inspection Techniques in SiC

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