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Stepped drift region thickness technique alters the drift region doping dose and its distribution, and therefore modulates the device's off-state characteristics. However, due to the sophisticated structure of the 2-D stepped drift region, the conventional 2-D modeling method is too complicated to provide a clear physical meaning. In this paper, based on the Effective Concentration Profile (ECP) theory, a simple but accurate 1-D ECP concept is proposed to unveil the physical insight of the stepped drift region technique and quantitatively analysis the influence of which on device breakdown characteristic. Therefore, the sophisticated 2-D structure affected by both RESURF and curvature effects is explored by a simple 1-D model with segmented-doped PN junction. Furthermore, based on the proposed analytical model, the designing criterion is proposed, which provide useful guidance for utilizing the benefit of the Stepped Drift Region Thickness technique and thus realizing the optimized surface electric field and breakdown voltage. The results obtained by the proposed model are found to be sufficiently accurate comparing with TCAD simulation results.

The drift region shape factor (Ld/t) plays a sophisticated role in affecting reduced surface field (RESURF) effect and breakdown characteristics. In this paper, based on the effective doping concentration (EDC) theory, an Improved EDC concept is proposed to explore the impact of shape factor on 2-D coupling effect in RESURF lateral power devices. The Improved EDC concept indicates that the sophisticated 2-D coupling in N-well resulting an effective N-I-P type drift region. Thus, the surface electric field basin may exist because of the expansion of vertical depletion region. The proposed model presents a more adaptive trait in describing 2-D coupling effect under various device structure parameters when compared to the conventional EDC model. Furthermore, a corresponding structure optimization criterion is provided to further improve the tradeoff between breakdown voltage, On-resistance and costs. The results obtained by the proposed model are found to be accurate comparing with TCAD simulation results.

The drift region doping profile plays a significant role in affecting the performance of lateral power devices on silicon-on-insulator (SOI) substrate. However, due to the modeling difficulty of the 2-D solution, the physical meaning of which still remains unclear. Thus, a novel effective doping profile concept is proposed to explore the physical insight of the surface electric field (EF) reshaping as a result of the step lateral doping profile. Through the effective concentration profile (ECP) theory, the sophisticated 2-D relationship between lateral step doping profile (SDP) and reduced surface field (RESURF) effect can be simplified to the fluctuation of the 1-D effective doping profile. A 1-D ECP model is presented accordingly to qualitatively and quantitatively explore the influence of SDP on the surface EF and breakdown voltage (BV) improvements. Furthermore, the designing criterion of drift region SDP is proposed with the help of the analytical model, which provides a useful guidance for realizing the optimized surface EF and BV in devices with SDP. [ABSTRACT FROM AUTHOR]

The layout-induced cylindrical breakdown may occur as a result of the multifinger or circular layout-induced 3-D curvature effect resulting in the breakdown voltage reduction of the power device significantly. In this paper, by using effective doping concentration (EDC) concept, the inherent 3-D problem is simplified as a 1-D problem. Based on the EDC concept, a 1-D analytical model is presented to qualitatively and quantitatively explore the impact of curvature effect on the breakdown mechanism of SOI lateral double diffused MOS. The analytical solutions are found out to be consistent with the simulation results well obtained from MEDICI, a commercial technology computer-aided design tool. To the best of our knowledge, the proposed model is the first 1-D model which can accurately describe the 3-D curvature effect. [ABSTRACT FROM AUTHOR]

Double-reduced surface field (D-RESURF) technique aims to increase the doping concentration of drift regions and maintain a high breakdown voltage. However, conventional 2-D models are too complicated and unable to elaborate its physicalmeaning.Hence, the D-RESURF effective doping concentration (EDC) theory is proposed in this paper to explore the physical insight of the D-RESURF effect by equating the sophisticated 2-D structure to a simple 1-DRESURFmodelwith segmented-dopedp-n junction.The EDC indicates that an NPNP structure may exist because of the influence of the P-top region. Thus, two electric field valleys and one electric field peak can be formed on the surface. Based on the theory, a 1-D analytical model is presented to qualitatively and quantitatively explore the impact of D-RESURF effect on breakdown mechanism of silicon on insulator lateral double diffusion MOS. The results obtained by the proposedmodel are found to be suf- ficiently accurate comparing with TCAD simulation results. [ABSTRACT FROM AUTHOR]