A Novel Dual-Mode Dual Trench MOSFET With Self-Adjustable Field Plate for Low EMI Noise and High Dynamic Avalanche Robustness

A novel dual-mode dual trench MOSFET (DDT-MOSFET) featuring shorted P-doping field plate (PFP) and N-doping field plate (NFP) is proposed. A parasitic depletion region capacitor and a parasitic MOSFET are introduced in the self-adjustable field plate (SFP). During turn-on, the DDT-MOSFET is in the split gate trench (SGT) mode with an electron inversion layer in the PFP, achieving low <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$C_{\mathrm { gd}}$ </tex-math></inline-formula>. During turn-off, the DDT-MOSFET is in the insulator pillar superjunction (I-SJ) mode with depleted PFP, achieving low electromagnetic interference (EMI) noise and high breakdown voltage (BV). Mode conversion is realized by the introduction of the SFP. By TCAD simulation, during turn-off, the proposed structure exhibits 33.9% improvement in BV, 42.8% reduction in maximum <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$dI_{\mathrm { D}}$ </tex-math></inline-formula>/dt and 44.1% reduction in overshoot voltage <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$(V_{\mathrm { O}})$ </tex-math></inline-formula> with same <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$E_{\mathrm { off}}$ </tex-math></inline-formula>, reducing EMI noise and improving dynamic avalanche robustness without deterioration of other electrical characteristics.