A novel high channel density trench power MOSFETs design by asymmetric wing-cell structure

A new cell structure Power MOSFET, which exhibits a lower on-state resistance and higher channel density than the conventional layout geometry, is proposed in this research. Vertical trench Power MOSFETs are generally designed by either squared (closed) cell or stripe (linear) cell geometry; each has its own advantages and drawbacks. In this study, we propose, fabricate, and analyze a "wing cell" structure Power MOSFET. In addition, the asymmetric wing cell structure is fabricated and compared with the conventional structures. The on resistance of the proposed devices can be further reduced. Both simulations and experiments show this structure have a lower on resistance than the original design. We also found that the avalanche characteristics of the proposed device are not sacrificed owing to higher channel density. One can also use this "wing-cell" concept to avoid the "closed cell" structure patents.