Promise and Challenges of High-Voltage SiC Bipolar Power Devices

Abstract

Although various silicon carbide (SiC) power devices with very high blocking voltages over 10 kV have been demonstrated, basic issues associated with the device operation are still not well understood. In this paper, the promise and limitations of high-voltage SiC bipolar devices are presented, taking account of the injection-level dependence of carrier lifetimes. It is shown that the major limitation of SiC bipolar devices originates from band-to-band recombination, which becomes significant at a high-injection level. A trial of unipolar/bipolar hybrid operation to reduce power loss is introduced, and an 11 kV SiC hybrid (merged pin-Schottky) diodes is experimentally demonstrated. The fabricated diodes with an epitaxial anode exhibit much better forward characteristics than diodes with an implanted anode. The temperature dependence of forward characteristics is discussed.

Impact of Wide-Bandgap Technology on Renewable Energy and Smart-Grid Power Conversion Applications Including Storage

“…From that same perspective, this paper reports on the learning done in recent years in some representative applications selected from the renewable energy applications domain (PV and wind). The findings clearly indicate that significant incremental benefits (not disruptive) can be drawn from WBG technology already as a drop-in replacement for Si, even with conventional standardized packaging solutions [1][2][3][4][5][6]. The higher initial price of the semiconductors is counter-balanced by savings in the filter elements and cooling, as well as by the possibility to do without free-wheeling diodes even in higher-voltage applications.…”

“…At higher voltage levels, SiC MOSFETs compete alone with Si IGBTs. Presently, widespread agreement exists, that SiC MOSFETs are very competitive with and can outperform Si IGBTs surely up to the 3.3 kV voltage class; beyond that rating, SiC is still of interest, but bipolar-type devices (e.g., SiC BJTs) are being earnestly considered [1].…”

Gate Current and Snapback of 4H-SiC Thyristors on N+ Substrate for Power-Switching Applications

“…The thermal conductivity of 4H-SiC is 3.3-4.9 W cm −1 K −1 , which is also greater than that of Si, which is 1.4-1.5 W cm −1 K −1 . Therefore, 4H-SiC is well-suited for use in power switches [8][9][10][11][12][13][14]. Recently, various research results related to the SiC power devices have been published.…”

“…Recently, various research results related to the SiC power devices have been published. The 10 kV SiC pin diode [11], 11 kV SiC merged pin-Schottky diode [12], SiC-based solid state circuit breaker [13], and intelligent control using SiC metal-oxide-semiconductor field-effect transistor for reduced electromagnetic interference generation [14] were reported.…”

MMC converter cells employing ultrahigh-voltage SiC bipolar power semiconductors

“…They are operated at approximately half the blocking voltage, meaning a maximum of 3.25 kV in the latter case. Ultrahigh-voltage (UHV) SiC bipolar devices are foreseen to be suitable for blocking voltages up to 50 kV [1] [2]. Consequently, the maximum operation voltage of converter cells could be increased by a factor of almost eight.…”