Surface-Passivation Effects on the Performance of 4H-SiC BJTs

• Published in: IEEE transactions on electron devices 2011-01, Vol.58 (1), p.259-265
• Main Authors: Ghandi, R, Buono, B, Domeij, M, Esteve, R, Schöner, A, Jisheng Han, Dimitrijev, S, Reshanov, S A, Zetterling, C-M, Östling, M
• Format: Article
• Language: English
• Subjects: Annealing; Applied sciences; Bipolar junction transistors (BJTs); Bipolar transistors; Breakdown; Charge; Devices; Dielectric, amorphous and glass solid devices; Electric potential; Electrical engineering, electronics and photonics; Electronic equipment and fabrication. Passive components, printed wiring boards, connectics; Electronics; Elektroteknik, elektronik och fotonik; Exact sciences and technology; Gain; Other multijunction devices. Power transistors. Thyristors; Oxides; Passivation; Performance evaluation; power transistor; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Semiconductor process modeling; Silicon carbide; TECHNOLOGY; TEKNIKVETENSKAP; Transistors; Voltage
• ISSN: 0018-9383; 1557-9646; 1557-9646
• DOI: 10.1109/TED.2010.2082712

In this brief, the electrical performance in terms of maximum current gain and breakdown voltage is compared experimentally and by device simulation for 4H-SiC BJTs passivated with different surface-passivation layers. Variation in bipolar junction transistor (BJT) performance has been correlated to densities of interface traps and fixed oxide charge, as evaluated through MOS capacitors. Six different methods were used to fabricate SiO 2 surface passivation on BJT samples from the same wafer. The highest current gain was obtained for plasma-deposited SiO 2 which was annealed in N 2 O ambient at 1100°C for 3 h. Variations in breakdown voltage for different surface passivations were also found, and this was attributed to differences in fixed oxide charge that can affect the optimum dose of the high-voltage junction-termination extension (JTE). The dependence of breakdown voltage on the dose was also evaluated through nonimplanted BJTs with etched JTE.