具有深槽超结的折叠漂移区SOI LIGBT新结构和耐压模型

The conventional high-voltage SOI (Silicon On Insulator) LIGBT (Lateral Insulated Gate Bipolar Transistor) has the disadvantages of huge size and high costs,introducing the lateral breakdown voltage into the vertical path is an effective method and research focus to reduce the size of device, but the satisfied results have not been obtained due to that the lateral blocking effect is poor and the distribution of the bulk electric field is ununiform, how to form an effective blocking layer is the design difficulty to be solved in high-voltage power device field. In this project, the interdigital dielectric trench is embedded into the active layer, and the problem of effective lateral blocking layer is solved by folding the drift region. Explore the physical nature of sustaining the breakdown voltage by folded drift region, and reveal the law to increase the breakdown voltage by electric field shielding effect of interface charge; Improve the distribution of bulk electric field and relieve the trade-off between the breakdown voltage and on-resistance by deep trench superjunction formed by ion implanting with angle, and the analytical optimization method between breakdown voltage and parameters of device is obtained; Improve the on-state voltage and turn-off time and eliminate the negative resistance effect by vertical voltage drop along the anode dielectric trench; Research the process of deep trench etching, silicon bonding and ion implanting with angle, and pursue the experiment of high-voltage, high-speed SOI LIGBT device with folded drift region. The completion of this project will achieve the effective introduction of lateral breakdown voltage into vertical path, and improve significantly the electrical properties of LIGBT, the research results have the great innovation value and practical significance.

常规高压SOI LIGBT功率器件具有尺寸巨大、成本高昂的缺点，把横向耐压引入纵向是减小器件尺寸的有效方法和研究热点，但由于横向阻挡效果不佳和体内电场严重非均匀，其研究尚未获得满意结果，如何形成有效横向阻挡层是高压功率器件领域亟待解决的设计难题。 本项目采用有源层嵌入叉指型介质槽，通过折叠漂移区解决可靠横向阻挡层的问题。探索折叠漂移区耐压的物理本质，揭示利用界面电荷的电场屏蔽效应提高耐压的规律；通过深槽离子角注入形成高深宽比超结，改善体内电场分布，缓解耐压和导通电阻间的约束关系，获得耐压和器件参数的解析优化方法；采用阳极介质槽提高纵向导通压降，消除负阻效应，改善导通压降和关断时间；研究深槽刻蚀、硅片键合和离子角注入等工艺，进行高压、高速的折叠漂移区SOI LIGBT的研制。 本项目的完成将实现把横向耐压有效引入纵向，显著提升LIGBT性能，其研究成果极富创新价值和现实意义。

把横向耐压引入纵向是减小器件尺寸的有效方法，但存在横向阻挡效果不佳和体内电场非均匀等问题，因此，如何形成有效横向阻挡层是高压功率器件领域亟待解决的设计难题。本项目采用有源层嵌入叉指型介质槽，通过折叠漂移区解决可靠横向阻挡层的问题，开展了折叠漂移区SOI器件新结构、制备工艺和模型等研究，分别研究了折叠漂移区耐压机理、超级结电荷补偿、制备工艺和模型、器件测试分析等方面。研究了介质槽纵向段电场分布与介质槽深度、间距，排列方式的关系，分析漂移区掺杂浓度对体电场分布的影响，获得提高横向耐压的设计方法，发现介质槽拐角积累高浓度的反型电荷，会增强介质层内电场，分别改善纵向和横向耐压；利用超级结提高优化漂移区掺杂浓度，降低导通电阻，研究介质槽结构参数、排列方式和超级结掺杂浓度对器件横向耐压的影响，改善耐压和导通电阻间折中关系；介质槽延长了有效漂移区长度，研究阳极介质槽深度与IGBT关断时间的关系，优化阳极介质槽结构参数和漂移区掺杂浓度，改善关断时间和导通压降之间的约束关系；设计器件版图，进行实验流片，测试与分析了器件的性能。测试结果表明，器件实现了优良的耐压性能，耐压超过1000V，阈值电压1.8V，关断时间700ns。此项成果为把横向耐压有效引入纵向提供新的思路，显著提升SOI高压器件性能。