SiC Double-Trench MOSFETs With Embedded MOS-Channel Diode

Abstract

A novel SiC double-trench MOSFET (DT-MOS) with embedded MOS-channel diode is proposed and investigated via TCAD simulations in this article. The parasitic body diode is free from activation when the device serves as a freewheeling diode, thus completely eliminating the bipolar degradation. Moreover, the proposed MOSFET features superior dynamic characteristics. The gate charge ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${Q}_{\text {G}}$ </tex-math></inline-formula> ) and gate-to-drain charge ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${Q}_{\text {GD}}$ </tex-math></inline-formula> ) are reduced by a factor of ~1.8 and ~3.9, respectively, when compared to the conventional state-of-the-art SiC DT-MOS. Combined with the slightly increased ON-resistance ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R}_{ \mathrm{\scriptscriptstyle ON}}$ </tex-math></inline-formula> ), remarkably improved figures of merit ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R}_{ \mathrm{\scriptscriptstyle ON}} \times {Q}_{\text {G}}$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R}_{ \mathrm{\scriptscriptstyle ON}}\times {Q}_{\text {GD}}$ </tex-math></inline-formula> are reduced by a factor of ~1.7 and ~3.7, respectively) are obtained in the proposed structure. When working as a switching device under 200 kHz, the proposed MOSFET could save nearly 64% of the total power losses, making it more conductive to high-frequency applications. In addition, the influence of parameters variation on the device performance is discussed as well.