基于部分复合埋层结构的横向变RESURF技术高压SOI LDMOS器件研究

Aiming at the contradictory requirements on the relevant structure parameters between the breakdown voltage (BV), the specific on-resistance (Ron,sp), and self-heating effect (SHE) for SOI high voltage LDMOS，a new concept of variable lateral RESURF caused by a partial compound buried layer structure (PCBL) is proposed, based on which, structure, model and process of the new device are researched. There are two major innovations in this study:. 1) The New SOI LDMOS based on the concept of variable lateral RESURF caused by PCBL is proposed. Firstly, electric field in the drift region is optimized by the different RESURF conditions from the PCBL, and the lateral BV is increased. Secondly, the optimized doping concentration is raised, and therefore, the Ron,sp is reduced at the on-state. In addition, the interface electric field of the top silicon layer is enhanced at the off-state and the vertical BV is increased. Finally, the thinner the top oxide layer and the polysilicon layer with a higher thermal conductivity in PCBL offers a lower SHE. A high performance device with higher BV, lower Ron,sp and fewer SHE is obtained.. 2) Breakdown model of the new structure is proposed. For revealing the inner nature in physical aspect how the new structure can offer the capability of high BV , low Ron,sp and few SHE, models of BV and Ron,sp are obtained by solving 2-D Poisson equation in different parts of the drift region, and the criterion of the variable lateral RESURF is derived. The proposed device will be experimentally fabricated. . This proposal is expected to propose a new scientific way and to establish some theoretical bases for obtaining a high performance SOI high voltage device with higher BV, lower Ron,sp and fewer SHE. It is a fundamental and applicative advanced research with international harmonization, which is of great significance.

针对SOI高压LDMOS耐压（BV）、比导通电阻（Ron,sp）及自热效应（SHE）矛盾关系，项目提出“基于部分复合埋层的横向变RRESURF”概念，研究基于该概念的器件结构、模型与流片验证。. 项目有两项创新：1）提出基于部分复合埋层的横向变RRESURF的SOI LDMOS新结构。利用横向变RESURF条件调制横向电场，提高横向耐压；增加优化的漂移区浓度，降低比导通电阻，并增加界面硅层电场而提高纵向耐压；复合埋层中较薄的埋氧层及高热导率的多晶硅加速热量传递，缓解SHE；2）提出新结构的耐压模型。着眼物理层面揭示新结构高BV、低Ron,sp、低SHE机理，分区求解漂移区泊松方程，建立模型，获得横向变RESURF判据。对新器件进行流片研制。. 项目期望寻找一种新的获得高BV、低Ron,sp及低SHE高性能SOI LDMOS器件的科学途径，是与国际同步的超前性应用基础研究。

基于SOI衬底的高压集成电路集SOI技术、微电子技术和功率电子技术于一体，近年来得到了迅速发展，在武器装备、航空航天、电力电子和其它高新技术产业有着极为广泛的应用前景。SOI高压集成电路的核心是SOI横向高压器件，对其的研究和发展一直是功率器件领域的热点。当前国际上针对SOI横向功率器件的研究主要集中在新器件结构和新理论模型两个方面，最为关注的是如何有效提高击穿电压、降低比导通电阻以及缓解自热效应。. 本项目提出基于部分复合埋层的横向变RESURF技术，获得一种能有效缓解击穿电压、比导通电阻以及自热效应对器件结构参数矛盾要求的途径，研究具有高压、低阻且具有良好热性能的SOI高压功率器件。项目设计具有复合埋层的SOI LDMOS器件结构，详细分析该器件的工作机理，获得各个结构参数与器件电学性能的定量关系，并通过求解泊松方程获得该器件的耐压模型。另外，项目基于体电场调制技术提出了一系列缓解功率器件耐压与比导通电阻矛盾关系的新型功率器件结构，相继提出具有浮空埋N+岛的横向功率器件、基于漂移区多重埋层的双栅SOI LDMOS器件，以及具有浮空场版的槽型场氧新器件等一系列新的器件结构。在硅基器件研究基础上，将研究拓展至宽禁带功率器件领域，提出集成异质结二极管的SiC VDMOS器件。项目圆满完成预期的研究目标。. 本项目共发表SCI检索期刊论文16篇，国际会议论文1篇，申请中国发明专利8项，其中已授权2项。项目共培养博士3名，硕士研究生8名，其中已经毕业硕士研究生6名。