Numerical Analysis of the LDMOS With Side Triangular Field Plate

Jiafei Yao,Yufeng Guo,Jun Zhang,Yu Deng,Zhenyu Zhang,Maolin Zhang

doi:10.1109/jeds.2019.2944868

Abstract

A Lateral Double-diffused Metal Oxide Semiconductor (LDMOS) with side triangular field plate (STFP) is proposed for improving the breakdown voltage ( BV ) and reducing the specific on-resistance ( $R_{on,sp}$ ). The main feature of the novel LDMOS is the STFPs at both ends of the drift region, and they are fabricated into the dielectric pillars. With the introduction of the STFPs, the electric field peaks at the P-well/N-drift and N+/N-drift junctions are reduced effectively. The STFPs together with the dielectric pillars modulate the surface and vertical electric field distributions, which enhances the BV . Meanwhile, the doping concentration of the silicon pillars in the drift region is optimized and thus reduces the $R_{on,sp}$ . The simulation results indicate that the BV of 379 V and the $R_{on,sp}$ of 37.3 $\text{m}\Omega \cdot $ cm2 are achieved by the STFP-LDMOS. The figure of merits ( FOM ) of the STFP-LDMOS is 2.7 times compared with the conventional LDMOS without STFPs. The STFP-LDMOS demonstrates a great trade-off between the $R_{on,sp}$ and BV .

Highlights

With the rapid development of the power integrated circuit, Lateral Double-diffused Metal Oxide Semiconductor (LDMOS) has been widely applied into various power devices owing to its advantages such as the high speed and the low parasitical effect [1]–[3]
The STFP-LDMOS with different LGFP and LDFP are simulated to investigate the influence of the side triangular field plate on the characteristics of the proposed LDMOS
For the STFP-OX-LDMOS, the field plate can improve the maximum breakdown voltage (BV) significantly when comparing the LDMOS without field plate and the CONV-LDMOS

Summary

INTRODUCTION

With the rapid development of the power integrated circuit, Lateral Double-diffused Metal Oxide Semiconductor (LDMOS) has been widely applied into various power devices owing to its advantages such as the high speed and the low parasitical effect [1]–[3]. The electric field and doping concentration of the proposed STFP-LDMOS have been modulated by the side triangular field plates, and the dielectric pillars [10]–[12]. It can be seen from the figure that the electric field peak P1 at the P-well/N-drift junction is YAO et al.: NUMERICAL ANALYSIS OF LDMOS WITH STFP. The novel LDMOS maintains the excellent switching characteristic compared with that of the CONV-LDMOS

RESULTS AND DISCUSSIONS

PROCESS REALIZATION

CONCLUSION