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Institute of Korean Electrical and Electronics Engineers (한국전기전자학회)
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Improved breakdown characteristics of Ga2O3 Schottky barrier diode using floating metal guard ring structure

플로팅 금속 가드링 구조를 이용한 Ga2O3 쇼트키 장벽 다이오드의 항복 특성 개선 연구

  • Choi, June-Heang (School of Electronic and Electrical Engineering, Hongik University) ;
  • Cha, Ho-Young (School of Electronic and Electrical Engineering, Hongik University)
  • Received : 2019.03.08
  • Accepted : 2019.03.25
  • Published : 2019.03.31
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Abstract

In this study, we have proposed a floating metal guard ring structure based on TCAD simulation in order to enhance the breakdown voltage characteristics of gallium oxide ($Ga_2O_3$) vertical high voltage switching Schottky barrier diode. Unlike conventional guard ring structures, the floating metal guard rings do not require an ion implantation process. The locally enhanced high electric field at the anode corner was successfully suppressed by the metal guard rings, resulting in breakdown voltage enhancement. The number of guard rings and their width and spacing were varied for structural optimization during which the current-voltage characteristics and internal electric field and potential distributions were carefully investigated. For an n-type drift layer with a doping concentration of $5{\times}10^{16}cm^{-3}$ and a thickness of $5{\mu}m$, the optimum guard ring structure had 5 guard rings with an individual ring width of $1.5{\mu}m$ and a spacing of $0.2{\mu}m$ between rings. The breakdown voltage was increased from 940 V to 2000 V without degradation of on-resistance by employing the optimum guard ring structure. The proposed floating metal guard ring structure can improve the device performance without requiring an additional fabrication step.

본 연구에서는 TCAD 시뮬레이션을 사용하여 산화갈륨 ($Ga_2O_3$) 기반 수직형 쇼트키 장벽 다이오드 고전압 스위칭 소자의 항복전압 특성을 개선하기 위한 가드링 구조를 이온 주입이 필요 없는 간단한 플로팅 금속 구조를 활용하여 제안하였다. 가드링 구조를 도입하여 양극 모서리에 집중되던 전계를 감소시켜 항복전압 성능 개선을 확인하였으며, 이때 금속 가드링의 폭과 간격 및 개수에 따른 항복전압 특성 분석을 전류-전압 특성과 내부 전계 및 포텐셜 분포를 함께 분석하여 최적화를 수행하였다. N형 전자 전송층의 도핑농도가 $5{\times}10^{16}cm^{-3}$이고 두께가 $5{\mu}m$인 구조에 대하여 $1.5{\mu}m$ 폭의 금속 가드링을 $0.2{\mu}m$로 5개 배치하였을 경우 항복전압 2000 V를 얻었으며 이는 가드링 없는 구조에서 얻은 940 V 대비 두 배 이상 향상된 결과이며 온저항 특성의 저하는 없는 것으로 확인되었다. 본 연구에서 활용한 플로팅 금속 가드링 구조는 추가적인 공정단계 없이 소자의 특성을 향상시킬 수 있는 매우 활용도가 높은 기술로 기대된다.

Keywords

JGGJB@_2019_v23n1_193_f0001.png 이미지

Fig. 1. Cross-sectional illustration of Ga2O3 SBD with floating metal guard rings. 그림 1. 플로팅 금속 가드링 구조을 갖는 Ga2O3 SBD 단면 모식도

JGGJB@_2019_v23n1_193_f0002.png 이미지

Fig. 2. Breakdown characteristics as a function of guard ring spacing (SGR ). 그림 2. SGR에 따른 항복 특성 변화

JGGJB@_2019_v23n1_193_f0003.png 이미지

Fig. 3. Electric field and potential distribution along the surface as a function of guard ring spacing (SGR ). 그림 3. SGR 에 따른 표면에서의 전계 및 포텐셜 분포

JGGJB@_2019_v23n1_193_f0004.png 이미지

Fig. 4. Breakdown characteristics as a function of the number of guard rings (NGR ). 그림 4. NGR 에 따른 항복 특성 변화

JGGJB@_2019_v23n1_193_f0005.png 이미지

Fig. 5. Electric field and potential distribution along the surface as function of guard ring number (NGR ). 그림 5. NGR 에 따른 표면에서의 전계 및 포텐셜 분포

JGGJB@_2019_v23n1_193_f0006.png 이미지

Fig. 6. (a) Breakdown voltage as functions of the number of guard rings (NGR ) and guard ring width (WGR ) and (b) breakdown voltage versus guard ring width (NGR = 5 = 5). 그림 6. (a) NGR = 5와 WGR 에 따른 항복전압 변화. (b) WGR 에 따른 항복전압 (NGR = 5)

JGGJB@_2019_v23n1_193_f0007.png 이미지

Fig. 7. Electric field and potential distribution as a function of length of guard ring metals(WGR ). 그림 7. WGR 변화에 따른 소자내의 전계 및 포텐셜 분포

JGGJB@_2019_v23n1_193_f0008.png 이미지

Fig. 8. Forward current-voltage characteristics with and without guard rings. 그림 8. 가드링 구조 유무에 따른 정전류-전압 특성

Table 1. Material properties of Ga2O3 in simulation. 표 1. 시뮬레이션에 사용된 Ga2O3의 물성

JGGJB@_2019_v23n1_193_t0001.png 이미지

References

  1. H. Morkoc, S. Strite, G. B. Gao, M. E. Lin, B. Sverdiov, and M. Burns, "Large-band-gap SiC, III-VI nitride, and II-VI ZnSe-based Semiconductor device technologies," Journal of Applied Physics, vol. 76, no. 3, pp. 1363-1398, 1994. DOI: 10.1063/1.358463
  2. M. Bhatangar, Peter K. McLarty, and Baliga, "Silicon Carbide High-Voltage (400 V) Schottky Barrier Diodes," IEEE ELECTRON DEVICE LETTERS, Vol. 13, no. 10, pp. 501-503, 1992. DOI: 10.1109/55.192814
  3. Masataka Higashiwaki, Kohei Sasaki, Hisashi Murakami, Yoshinao Kumagai, Akinori Koukitu, Akito Kuramata, Takekazu Masui and Shigenobu Yamakoshi, "Recent progress in $Ga_2O_3$ power devices," Semiconductor Science and Technology, Vol. 31, no. 3, P.034001, 2016. DOI: 10.1088/0268-1242/31/3/034001
  4. J. B. Varley, J. R. Weber, A. Janotti, and C. G. Van de Walle, "Oxygen vacancies donor impurities in ${\beta}$-$Ga_2O_3$," Applied Physics Letters, Vol. 97, no. 14, P. 142106, 2010. DOI: 10.1063/1.3499306
  5. Ranjith K. Ramachandran, Jolien Dendooven, Jonas Btterman, Sreeprasanth Pulinthanathu Sree, Drik Poelman, Johan A. Martens, Hilde Poelman and Christophe Detavernier, "Plasma enhanced atomic layer deposition of $Ga_2O_3$ thin films," Journal of Materials Chemistry A, Vol. 2, pp. 19232-19238, 2014. DOI: 10.1039/c4ta90219j
  6. Kanika Arora, Neeraj Goel, Mahesh Kumar, and Muskesh Kumar, "Ultrahigh Performance of Self-Powered ${\beta}$-$Ga_2O_3$ Thin Film Solar-Blind Photodetector Grown on Cost-Effective Si Substrate Using High-Temperature Seed Layer," ACS Photonics, Vol. 5, no. 6, pp. 2391-2401, 2018. DOI: 10.1021/acsphotonics.8b00174
  7. J.-H, Choi, C.-H. Cho, H.-Y. Cha, "Design consideration of high voltage $Ga_2O_3$ vertical Schottky barrier diode with field plate," Results in Physics, Vol. 9, pp. 1170-1171, 2018. DOI: 10.1016/j.rinp.2018.04.042
  8. Junsung Park, Sung-Min Hong, "Simulation Study of Enhancement Mode Multi-Gate Vertical Gallium Oixde MOSFETs," Journa of Solid State Science and Technology, Vol. 8, no. 7, pp. 3116-3121, 2019. DOI: 10.1149/2.0181907jss
  9. Masahiro Orita, Hiromichi Ohta, Msashiro Hirano, and Hideo Hosono, "Deep-ultra transparent conductive ${\beta}$-$Ga_2O_3$ thin films," Applied Physics Letters, Vol. 77, no. 25, p. 4166, 2000. DOI: 10.1063/1.1330559
  10. Hitoshi Umezawa, "Recent advances in diamond power semiconductor devices," Materials Science in Semiconductor Processing, Vol. 78, pp. 147-156, 2018. DOI: 10.1016/j.mssp.2018.01.007
  11. Jiancheng Yang, F. Ren, Marko Tadjer, S. J. Pearton, and A. Kuramata, "2300V Reverse Breakdown Voltage $Ga_2O_3$ Schottky Rectifiers," ECS Journal of Solid State Science and Technology, Vol. 7, no. 5, Q92-Q96, 2018. DOI: 10.1149/2.0241805jss
  12. Neil Moser, Jonathan McCandless, Antonio Crespo, Kevin Leedy, Andre Green, Adam Neal, Shin Mou, Elaheh Ahmadi, James Speck, Kelson chabak, Nathalia Peixoto, and Gregg Jessen, "Ge-Doped ${\beta}$-$Ga_2O_3$," IEEE ELECTRON DEVICE LETTERS, Vol. 38, no. 6, pp. 775-778, 2018. DOI: 10.1109/LED.2017.2697359
  13. Nan Ma, Nicholas Tanen, Amit Verma, Zhi Guo, Tengfei Luo, Huili (Grace) Xing, and Debdeep Jena, "Intrinsic electron mobility limits in ${\beta}$-$Ga_2O_3$," Applied Physics Letters, Vol. 109, no. 21, p. 212101, 2016. DOI: 10.1063/1.4968550
  14. C. E. Weitzel, J. W. Palmour, C. H. Carter, K. Moore, K. K. Nordquist, S. Allen, C. Thero, and M. Bhatnagar, "Silicon carbide high-power devices," IEEE Transactions on Electron Devices, Vol. 43, no. 10, pp. 1732-1741, 1996. DOI: 10.1109/16.536819
  15. Krishnendu Chosh, and Uttam Singisetti "Impact ionization in ${\beta}$-$Ga_2O_3$," Journal of Applied Physics, vol. 124, no. 8, p. 085707, 2018. DOI: 10.1063/1.5034120