SiC trench MOSFET with heterojunction diode for low switching loss and high short‐circuit capability

Abstract

A SiC trench MOSFET with a merged heterojunction diode is proposed and numerically analysed here. The merged heterojunction diode can effectively suppress the turn-on of the parasitic body diode in the proposed SiC trench MOSFET. In addition, a P + shield layer surrounding the gate oxide layer can dramatically alleviate the gate oxide corner from the concentration of the electric field and improve the static and dynamic performances of the proposed device. As a result, not only the breakdown voltage is increased by 24% but also the miller charge and the switching losses of the proposed structure are reduced by 43 and 48.6%, respectively, when compared with those of the conventional SiC trench MOSFET with a grounded P + shield layer. Moreover, the short-circuit capability and its failure mechanism are numerically studied for the proposed structure. Finally, a feasible fabrication procedure is provided to realise the fabrication of this new device.

Simulative Researching of a 1200V SiC Trench MOSFET With an Enhanced Vertical RESURF Effect

“…7 shows the gate charge (Qg) of the two devices evaluated by the testing circuit in the inset. The devices' areas are both set as 1cm 2 . The Qg and the gate-to-drain charge (Qgd) of the proposed device are 677 nC/cm 2 and 144 nC/cm 2 , respectively, which are far smaller than those of C-TMOS (906 nC/cm 2 and 302 nC/cm 2 ).…”

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

“…Silicon carbide (SiC) material, known for its wide bandgap, high critical breakdown electric field strength and high thermal conductivity, replaces silicon as a new generation power semiconductor material [1][2][3]. The 4H-SiC trench MOSFET (TMOS) has gained significant attention as an emerging power semiconductor device with advantages such as high breakdown voltage (BV), high current capacity, and fast switching speed, which made it widely employed in power-integrated circuits [4][5][6][7][8]. However, achieving high BV in SiC devices typically requires a long drift region and low drift region doping concentration (N D ), resulting in a significant increase in specific on-resistance (R on,sp ).…”

Numerical demonstration of SiC trench MOSFET with integrated heterojunction diode for enhanced performance

“…21) In addition, it is also an effective measure to handle this problem by introducing a heterojunction diode (HD) into the SiC MOSFET. The barrier height for electrons Φ BN in a p-type polysilicon/n-type SiC HD [22][23][24] could be reduced to about 1.48 eV, resulting in a small V F for the device. While integrating an n-type polysilicon/n-type SiC HD 25) is also proposed to further decrease V F due to the lower Φ BN of about 0.68 eV across the n-type HD.…”