Search

A novel low specific on-resistance (Ron,sp) lateral double-diffused metal oxide semiconductor (LDMOS) with a buried improved super-junction (BISJ) layer is proposed. A super-junction layer is buried in the drift region and the P pillar is split into two parts with different doping concentrations. Firstly, the buried super-junction layer causes the multiple-direction assisted depletion effect. The drift region doping concentration of the BISJ LDMOS is therefore much higher than that of the conventional LDMOS. Secondly, the buried super-junction layer provides a bulk low on-resistance path. Both of them reduce Ron,sp greatly. Thirdly, the electric field modulation effect of the new electric field peak introduced by the step doped P pillar improves the breakdown voltage (BV). The BISJ LDMOS exhibits a BV of 300 V and Ron,sp of 8.08 mΩ·cm2 which increases BV by 35% and reduces Ron,sp by 60% compared with those of a conventional LDMOS with a drift length of 15 μm, respectively. [ABSTRACT FROM AUTHOR]

A new silicon-on-insulator (SOI) power lateral MOSFET with a dual vertical field plate (VFP) in the oxide trench is proposed. The dual VFP modulates the distribution of the electric field in the drift region, which enhances the internal field of the drift region and increases the drift doping concentration of the drift region, resulting in remarkable improvements in breakdown voltage (BV) and specific on-resistance (Ron,sp). The mechanism of the VFP is analyzed and the characteristics of BV and Ron,sp are discussed. It is shown that the BV of the proposed device increases from 389 V of the conventional device to 589 V, and the Ron,sp decreases from 366 mΩ·cm2 to 110 mΩ·cm2. [ABSTRACT FROM AUTHOR]

We present a novel numerical model and simulate preliminarily the charging process of a polymer subjected to electron irradiation of several 10 keV. The model includes the simultaneous processes of electron scattering and ambipolar transport and the influence of a self-consistent electric field on the scattering distribution of electrons. The dynamic spatial distribution of charges is obtained and validated by existing experimental data. Our simulations show that excess negative charges are concentrated near the edge of the electron range. However, the formed region of high charge density may extend to the surface and bottom of a kapton sample, due to the effects of the electric field on electron scattering and charge transport, respectively. Charge trapping is then demonstrated to significantly influence the charge motion. The charge distribution can be extended to the bottom as the trap density decreases. Charge accumulation is therefore balanced by the appearance and increase of leakage current. Accordingly, our model and numerical simulation provide a comprehensive insight into the charging dynamics of a polymer irradiated by electrons in the complex space environment. [ABSTRACT FROM AUTHOR]

An analytical model for a novel triple reduced surface field (RESURF) silicon-on-insulator (SOI) lateral double-diffused metal–oxide–semiconductor (LDMOS) field effect transistor with n-type top (N-top) layer, which can obtain a low on-state resistance, is proposed in this paper. The analytical model for surface potential and electric field distributions of the novel triple RESURF SOI LDMOS is presented by solving the two-dimensional (2D) Poisson’s equation, which can also be applied to single, double and conventional triple RESURF SOI structures. The breakdown voltage (BV) is formulized to quantify the breakdown characteristic. Besides, the optimal integrated charge of N-top layer (Qntop) is derived, which can give guidance for doping the N-top layer. All the analytical results are well verified by numerical simulation results, showing the validity of the presented model. Hence, the proposed model can be a good tool for the device designers to provide accurate first-order design schemes and physical insights into the high voltage triple RESURF SOI device with N-top layer. [ABSTRACT FROM AUTHOR]

A low specific on-resistance SOI LDMOS with a novel junction field plate (JFP) is proposed and investigated theoretically. The most significant feature of the JFP LDMOS is a PP—N junction field plate instead of a metal field plate. The unique structure not only yields charge compensation between the JFP and the drift region, but also modulates the surface electric field. In addition, a trench gate extends to the buried oxide layer (BOX) and thus widens the vertical conduction area. As a result, the breakdown voltage (BV) is improved and the specific on-resistance (Ron,sp) is decreased significantly. It is demonstrated that the BV of 306 V and the Ron,sp of 7.43 mΩ·cm2 are obtained for the JFP LDMOS. Compared with those of the conventional LDMOS with the same dimensional parameters, the BV is improved by 34.8%, and the Ron,sp is decreased by 56.6% simultaneously. The proposed JFP LDMOS exhibits significant superiority in terms of the trade-off between BV and Ron,sp. The novel JFP technique offers an alternative technique to achieve high blocking voltage and large current capacity for power devices. [ABSTRACT FROM AUTHOR]

This paper describes the successful fabrication of 4H-SiC junction barrier Schottky (JBS) rectifiers with a linearly graded field limiting ring (LG-FLR). Linearly variable ring spacings for the FLR termination are applied to improve the blocking voltage by reducing the peak surface electric field at the edge termination region, which acts like a variable lateral doping profile resulting in a gradual field distribution. The experimental results demonstrate a breakdown voltage of 5 kV at the reverse leakage current density of 2 mA/cm2 (about 80% of the theoretical value). Detailed numerical simulations show that the proposed termination structure provides a uniform electric field profile compared to the conventional FLR termination, which is responsible for 45% improvement in the reverse blocking voltage despite a 3.7% longer total termination length. [ABSTRACT FROM AUTHOR]