SiGe HBT单粒子效应电荷收集机制及其关键影响因素研究

SEE （Single Event Effects ) is defined as deleterious effects in the devices caused by the deposition of energy within electronic devices by a single energetic particle. Silicon Germanium (SiGe) Heterojunction Bipolar Transistor (HBT) technology has become an important semiconductor technology for use at extreme temperatures,Silicon Germanium (SiGe) Heterojunction Bipolar Transistor (HBT) technology has become an important semiconductor technology for use at extreme temperatures, together with its CMOS integration capability。SiGe HBT has been attractive for space applications because of its high performance. SiGe HBTs were found robust to displacement damages and total ionizing dose radiation. But, high speed SiGe HBT digital logic circuits were found to be vulnerable to SEU . Hence it is important to study the Single Event Effects on SiGe HBTs. SiGe HBT logic circuits were prone to SEE , and many surprising and　unexplained phenomena were observed. SEU-induced charge collection in SiGe HBTS　and reveal factots will be investigated in this work.Investigations into SEE induced charge collection in Silicon Germanium (SiGe) heterojunction bipolar transistors (HBT) are made through three-dimensional (3-D) device simulation. Ion microbeam measurements and TCAD simulations will be used to investigate the impact of the isolation on charge collection for events crossing the differnet structure , with a focus on lightly ionizing ions at various angles of incidence relative to the normal of the die surface. The charge collection characteristics in a state-of-the-art　at home for SiGe HBT will be explained. The simulated data will be compared with the charge collection results from the　microbeam experiments with adjustment of recombination parameters, fitting to microbeam data was, achieved on some HBTs. The sensitive area of charge collection for each terminal will be identified based on analysis of the device structure and simulation results. The insights gained through this work will offer a new understanding of the mechanisms . Another type of radiation hardening is Radiation Hardening By Design (RHBD), where the changes are made in the layout only. In this work we hope to introduce an RHBD for SiHe HBT.Accurate measurement of a fundamental result can be used to build realistic device simulations and thereby contribute to higher quality single-event effects studies at the circuit and system levels.

单粒子效应是空间辐射环境中的高能粒子与微电子器件相互作导致器件失效的一种损伤效应。在极端空间环境下，如低温-180℃～＋125℃，SiGe 器件在卫星、深空探测设备中有可能替代目前的体硅器件，有可能去掉体硅器件携带的保温装置，进而降低发射成本同时扩展卫星远程功能功能。SiGe HBT表现出良好的抗总剂量和位移损伤效应能力。但由于其工艺制作、结构等新的特征，单粒子效应是影响其空间应用的关键因素。本课题针对SiGe HBT 单粒子效应的新特点，通过数值模拟仿真和单粒子微束实验相结合，对高能粒子电荷能量沉积引起的SiGe 器件电参数退化进行机理研究，深入揭示SiGe HBT器件不同于体硅器件的复杂的单粒子效应损伤微观机制；研究微束辐照下器件的瞬态响应过程，对数值模拟建立的损伤模型互相验证，进一步对单粒子效应失效机理给出科学的解释；为器件、电路和系统级抗单粒子效应的设计加固提供参考。

异质结带隙渐变使锗硅异质结双极晶体管（SiGe HBT）具有良好的温度特性，可承受−180~+200℃的极端温度，在空间极端环境领域具有诱人的应用前景。然而，工作于太空环境的微电子器件与电路将不可避免的遭受各种宇宙射线和高能粒子的电离辐射影响，引起性能退化而给航天器电子系统的可靠性带来重大隐患。SiGe HBT由于材料和工艺结构的新特征，对单粒子效应非常敏感，其单粒子效应表现出不同于体硅器件的复杂的电荷收集机制，成为制约其空间应用的关键因素。为了保证应用于空间飞行器，特别是飞行器壳体外部的SiGe HBT及相关电路的可靠性，有必要对SiGe HBT单粒子效应的损伤机理进行深入研究，并定位其单粒子效应的敏感区域。本项目针对SiGe HBT器件，开展了空间单粒子效应研究：采用计算机数值模拟方法分析了SiGe HBT单粒子效应物理机制，获取了其单粒子效应敏感区域，研究了影响SiGe HBT单粒子效应的关键因素；采用激光微束与重离子微束模拟单粒子效应实验方法研究了SiGe HBT单粒子效应损伤响应，验证了SiGe HBT单粒子效应敏感体积。结果表明，SiGe HBT对空间电离辐射单粒子效应十分敏感，离子入射极易诱发电流瞬变和电荷收集效应。偏置状态、离子入射角度以及极端环境等因素会对SiGe HBT单粒子效应产生复杂的影响。激光微束辐照可以有效观测到单粒子效应敏感区，但其引起材料内部载流子电离的物理机制与重离子不同。重离子微束辐照可以有效评估SiGe HBT空间单粒子效应。项目采用理论与实践相结合的方法，为国产SiGe HBT空间实际应用，以及抗辐射加固技术的研究提供了指导与支持。