A novel SiC high-k superjunction power MOSFET integrated Schottky barrier diode with improved forward and reverse performance

Abstract

A new SiC superjunction power MOSFET device using high-k insulator and p-type pillar with an integrated Schottky barrier diode (Hk-SJ-SBD MOSFET) is proposed, and has been compared with the SiC high-k MOSFET (Hk MOSFET), SiC superjuction MOSFET (SJ MOSFET) and the conventional SiC MOSFET in this article. In the proposed SiC Hk-SJ-SBD MOSFET, under the combined action of the p-type region and the Hk dielectric layer in the drift region, the concentration of the N-drift region and the current spreading layer can be increased to achieve an ultra-low specific on-resistance (R on,sp). The integrated Schottky barrier diode (SBD) also greatly improves the reverse recovery performance of the device. TCAD simulation results indicate that the R on,sp of the proposed SiC Hk-SJ-SBD MOSFET is 0.67 mΩ·cm2 with a 2240 V breakdown voltage (BV), which is more than 72.4%, 23%, 5.6% lower than that of the conventional SiC MOSFET, Hk SiC MOSFET and SJ SiC MOSFET with the 1950, 2220, and 2220 V BV, respectively. The reverse recovery time and reverse recovery charge of the proposed MOSFET is 16 ns and18 nC, which are greatly reduced by more than 74% and 94% in comparison with those of all the conventional SiC MOSFET, Hk SiC MOSFET and SJ SiC MOSFET, due to the integrated SBD in the proposed MOSFET. And the trade-off relationship between the R on,sp and the BV is also significantly improved compared with that of the conventional MOSFET, Hk MOSFET and SJ MOSFET as well as the MOSFETs in other previous literature, respectively. In addition, compared with conventional SJ SiC MOSFET, the proposed SiC MOSFET has better immunity to charge imbalance, which may bring great application prospects.

Investigations of 4H‐SiC trench MOSFET with integrated high‐K deep trench and gate dielectric

“…From this figure, it can be observed that both the BV and R on,sp are decreased when the interface charge density varies from −10×10 11 cm −2 to 10×10 11 cm −2 , this is because the interface charge alters the effective doping concentration of the device. A negative interface charge density implies a decrease in effective doping concentration, while a positive interface charge density implies an increase in effective doping concentration [23]. For TMOS, higher doping concentration in the drift region leads to lower BV and R on,sp .…”

A Novel Deep-Trench Super-Junction SiC MOSFET with Improved Specific On-Resistance

“…Meanwhile, novel structures have been published to further improve device performance. A device formed with a high-k material offers a wider charge balance window than a novel SJ MOSFET [ 14 , 15 ] and, hence, reduces manufacturing error. Recently, deep-trench SJ MOSFETs with better short-circuit performance and electric field distribution have also been obtained [ 16 , 17 ].…”

A novel 4H‐SiC accumulation mode MOSFET with ultra‐low specific on‐resistance and improved reverse recovery capability

“…And the commercial SiC MOSFET (metal-oxide-semiconductor field-effect transistor), JFET (junction field-effect transistor), and SBD (Schottky barrier diode) products are already widely used and are extremely significant components of the power electronics systems [4][5][6][7]. And the advancement of SiC wafers and process technologies provide more possibilities for the design and realization of SiC power devices, and the SiC trench MOSFETs have also been commercialized and have been extensively researched [8][9][10][11][12]. However, the issues of the oxidation process of SiC introduce high interface states density at the SiO 2 /SiC interface and low electron mobility of the channel inversion layer in the SiC trench MOSFETs still exists.…”