超高压碳化硅光触发晶闸管关键技术研究

In view of the fact that the high-voltage silicon Light Triggered Thyristor (LTT) has approached the physical limitation of silicon material. In order to improve the sensitivity for the purpose of the realization of SiC LTT triggered by the UV LED light source basing on the characteristics of 4H-SiC material and the operating principles of LTT, A novel structure of SiC Ultra-high Voltage (UHV) LTT with multistage amplifying gates and the new composite junction termination which have combined circular-arc mesa structure with three-zone junction termination extension (JTE) modulated by charges is proposed. The theoretical analyses and experiments will be carried out in this study. In this project, the key models of physical and analysis will be established by considering parameters affecting the photoelectric characteristic and the temperature characteristic to investigate the operation mechanism and to optimize the device structure by means of numerical simulation, and thereby improve the theoretical research of operation mechanism of the device. The theoretical models of the effective charge-modulated for the UHV junction termination will be established and improved by investigating the process robustness of the new composite junction termination. A large number of the process experiments will be done to develop circular-arc mesa process technology and to optimize RIE etching technology and surface passivation technology. Then, the technological process, the layouts and photo-masks will be designed and produced respectively for tape-out and experimental verification of the operation mechanism of the device. Furthermore, the device process and implementation scheme will be verified and established by testing and analyzing of the device..In a word, Once succeeded, the research results of this project would provide the theoretical references and technical approach for the design, and manufacture and application of UHV SiC LTT for our country.

鉴于高压Si光触发晶闸管(LTT)的特性已逼近其材料的物理极限。本项目基于4H-SiC材料特性和LTT工作原理，以具有圆弧台面与电荷调制功能的3区JTE新型复合结构为结终端，以提高灵敏度，实现UV LED光源触发为目标，提出一种具有多级放大门极的超高压SiC LTT新结构。并拟从理论和实验两方面对其展开研究。具体包括建立影响光电特性、温度特性等关键物理参数及特性分析模型，基于数值仿真，对器件机理和器件结构进行分析与优化设计，完善器件工作机理的理论研究。研究新型复合结终端的工艺鲁棒性，建立并完善超高压结终端的有效电荷调制理论模型。通过工艺实验，开发SiC圆弧台面技术，优化RIE刻蚀和表面钝化工艺。设计工艺流程，制版并进行流片验证，通过测试分析，验证并完善超高压SiC LTT的理论，确立器件工艺实施方案。研究结果为我国超高压SiC LTT的设计、制造及应用提供理论指导和技术途径。

鉴于高压Si光触发晶闸管(LTT)的特性已逼近其材料的物理极限。本项目基于4H-SiC材料特性和LTT工作原理，以具有圆弧台面与电荷调制功能的多区JTE新型复合结构为结终端，以提高灵敏度，实现UV LED光源触发为目标，从理论和实验两方面对提出的具有放大门极的超高压SiC LTT新结构开展研究，为我国SiC LTT器件的发展提供了可行方案。. 本研究首先建立影响光电特性、温度特性的关键物理参数模型及特性分析模型。然后，分别对10KV SiC主晶闸管、放大门极、光触发晶闸管等单元的工作机理和结构开展了理论分析、建模和仿真研究。提出了低高低掺杂的短基区电控晶闸管新结构，使开通时间低至37ns；提出沟槽结隔离放大门极改进结构，缩小隔离区面积，完成了改进结构的耐压机理分析以及极隔离区钝化层界面电荷和辐照剂量对器件阻断特性的影响研究；提出了p-NiO/n-SiC结替代SiC pn同质结的新方案，解决了p型SiC受主不完全离化造成的SiC pn结空穴注入效率低的问题；针对LED弱光触发开通时间长的难点，提出空穴注入增强与空穴输运增强新技术，提高pnp耦合晶体管的增益，缩短弱光触发的开通时间，完善了超高压SiC LTT的工作机理。其次，研究了新型弧形台面的电荷调制JTE复合结终端的工艺鲁棒性，研究了钝化层界面电荷及γ辐照对终端耐压特性的影响，完善超高压结终端的有效电荷调制理论模型，建立了可靠的超高压LTT新型复合结终端结构设计方法，为今后超高压SiC器件的终端设计与优化提供了理论依据。最后设计了工艺流程，制版并进行了光触发晶闸管单元的流片，首次实现了双层n短基区SiC LTT的UV LED（100mW/cm2@365nm）光触发，开通延迟时间小于15μs。该项目的研究成果为我国超高压SiC LTT的设计与制造提供理论指导和技术途径，提升了我国在该领域的影响力。