High-Voltage (2.8 kV) Implantation-Free 4H-SiC BJTs With Long-Term Stability of the Current Gain

• Published in: IEEE transactions on electron devices Vol. 58; no. 8; pp. 2665 - 2669
• Main Authors: Ghandi, R., Buono, B., Domeij, M., Zetterling, C., Ostling, M.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.08.2011; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Bipolar junction transistors (BJT); Breakdown; Degradation; Devices; Diodes; Direct current; Electric potential; Electronic equipment and fabrication. Passive components, printed wiring boards, connectics; Electronics; Exact sciences and technology; Gain; Integrated circuits; Junctions; Other multijunction devices. Power transistors. Thyristors; power transistor; Resistance; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Silicon carbide; Stress; Switching; Transistors; Voltage; Base emitter junction; Rise time; Diode; Power electronics; Switching; Bipolar transistor; Power transistor; Junction transistors; Temperature coefficient; Silicon carbide; High voltage; Disruptive voltage; Direct current; Decay time; Junction termination; Current gain; Damaging; Bipolar junction transistors (BJT)
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2011.2154332

In this paper, implantation-free 4H-SiC bipolar junction transistors (BJTs) with a high breakdown voltage of 2800 V have been fabricated by utilizing a controlled two-step etched junction-termination extension in the epitaxial base layer. The small-area device shows a maximum direct-current (dc) gain of 55 at J C = 0.33 A (J C = 825 A/cm 2 ) and V CESAT = 1.05 V at I c = 0.107 A that corresponds to a low specific ON-state resistance of 4 mΩ · cm 2 . The large-area device has a maximum dc gain of 52 at J C = 9.36 A (J C = 289 A/cm 2 ) and V CESAT = 1-14 V at I c = 5 A that corresponds to a specific ON-state resistance of 6.8 mΩ · cm 2 . In addition, these devices demonstrate a negative temperature coefficient of the current gain (β = 26 at 200 °C) and a positive temperature coefficient of the specific ON-state resistance (R ON = 10.2 mΩ · cm 2 at 200 °C). The small-area BJT shows no bipolar degradation and a low-current-gain degradation after a 150-h stress of the base-emitter diode with a current level of 0.2 A (J E = 500 A/cm 2 ). Furthermore, the large-area BJT shows a V CE fall time of 18 ns during turn-on and a V CE rise time of 10 ns during turn-off for 400-V switching characteristics.