Evaluation of Effect of Mechanical Stress on Stacking Fault Expansion in 4H-SiC P-i-N Diode

Abstract:

Single Shockley stacking faults (SSFs) expand from basal plane dislocations (BPDs) under forward current operation of 4H-SiC bipolar devices, giving rise to a reliability deterioration mode called “bipolar degradation”. Several groups have proposed models for the expansion of SSFs, in which the SSFs expand when electron-hole pair recombination takes place at BPDs. Maeda proposed a formulation of SSF expansion that includes stacking fault energy. However, the mechanisms by which mechanical stress affects the expansion of SSFs are unclear. In this paper, we evaluated the “expansion threshold current” of bar-shaped SSFs in a mechanical stress field using a p-i-n diode fabricated on 4H-SiC. To confirm the effect of mechanical stress on the threshold current for bar-shaped SSF expansion, a SiC-p-i-n diode was evaluated by the four-point bending method. Experimental results show that the threshold current of SSFs decreases or increases by more than 100 A/cm² depending on the direction of the applied stress of SSFs. This result indicates that mechanical stress is an important factor for SiC bipolar device design.

• Periodical: Materials Science Forum (Volume 963)
• Pages: 288-293
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.963.288
• Online since: July 2019
• Authors: Akihiro Goryu*, Akira Kano, Mitsuaki Kato, Chiharu Ota, Aoi Okada, Johji Nishio, Satoshi Izumi, Kenji Hirohata
• Keywords: Bipolar Degradation, Bipolar Device, Four-Point Bending, P-i-N Diode, Resolved Shear Stress, Single Shockley Stacking Fault

References

[1] M. Skowronski and S. Ha, Degradation of hexagonal silicon-carbide-based bipolar devices, J. of Appl. Phys. 99 (2006) 011101.

DOI: 10.1063/1.2159578

[2] T. Kimoto, Material science and device physics in SiC technology for high-voltage power devices, J. J. Appl. Phys. 54 (2015) 040103.

DOI: 10.7567/jjap.54.040103

[3] K. Maeda, S. Takeuchi, Enhanced glide of dislocations in GaAs single crystals by electron beam irradiation, J. J. Appl. Phys. 20 (1981) 165-168.

DOI: 10.1143/jjap.20.l165

[4] T. Miyanagi, H. Tsuchida, I. Kamata, T. Nakamura, K. Nakayama, R. Ishii, and Y. Sugawara, Annealing effects on single Shockley faults in 4H-SiC, Appl. Phys. Lett. 89, (2006) 062104.

DOI: 10.1063/1.2234740

[5] A. Goryu, M. Kato, A. Kano, S. Izumi and K. Hirohata, Evaluation method for mechanical stress dependence of the electrical characteristics of SiC MOSFET for electro-thermal-structural coupled analysis, ASME 2017 International Mechanical Engineering Congress and Exposition (IMECE), Tampa, USA, 10 (2017) 13-19.

DOI: 10.1115/imece2017-72027

[6] K. Maeda, in Materials and Reliability Handbook for Semiconductor Optical and Electron Devices, Springer New York, New York, 2013, 253-263.

[7] K. Maeda, R. Hirano, Y. Sato and M Tajima, Separation of the driving force and radiation-enhanced dislocation glide in 4HSiC, Materials Science Forum 725 (2012) 35-40.

DOI: 10.4028/www.scientific.net/msf.725.35

[8] M. Peach and J. S. Koehler, The Forces Exerted on Dislocations and the Stress Fields Produced by Them, Phys. Rev. 80 (1950) 436-439.

DOI: 10.1103/physrev.80.436

[9] P.M Anderson, J. P Hirth, J. Lothe, Theory of dislocations, third ed., Cambridge university press, Cambridge, 2017,79-81.