Evaluation of Enhanced Low Dose Rate Sensitivity in Fourth-Generation SiGe HBTs

Abstract

The total ionizing dose response of 4th-generation SiGe HBTs is assessed at both low and high dose rates to evaluate enhanced low dose rate sensitivity (ELDRS) in a new SiGe BiCMOS technology. Both device and circuit results are presented. A bandgap reference circuit topology is chosen to monitor for ELDRS in TID-induced collector current shifts, which have previously been reported in low dose rate studies of SiGe HBTs. The results in this paper also cover previous technology generations from this foundry in order to incorporate a broader view of dose rate effects in SiGe HBTs. No indication of ELDRS was found in any technology generation.Index Terms-Bandgap reference (BGR), enhanced low dose rate sensitivity (ELDRS), high dose rate (HDR), low dose rate (LDR), silicon-germanium heterojunction bipolar transistor (SiGe HBT), total ionizing dose (TID).

3D Simulation Study on the Mechanism of Influence Factor of Total Dose Ionizing Effect on SiGe HBT

“…月球-180℃～+120℃的典型极端宽温范围内，SiGe 器件使相关航天探测设备具 备去掉庞大保温装置的可能，进而降低发射成本 [4][5] 。因此，不同于传统设计中 无源器件作为舱外设备的主流，SiGe HBT 具备了有源器件舱外应用的可能性， 能够显著提高平台的有效载荷质量， 实现信息获取、 处 理 与传输能力的大幅提升。 同时，SiGe HBT 利用能带工程，在增益、频响特性、噪声和线性度等方面都表 现出优异的电学性能；其还与 Si CMOS 工艺具有良好的兼容性，对于不同电路 应用具有很强的适用性，成为空间极端环境应用中的有力竞争者之一 [6][7] 。 然而， 工作于空间辐射环境中的电子系统不可避免的要遭受电离辐射的影响。 尤其当器件应用于卫星壳体外部时，短时间内遭受的粒子辐射急剧增加，电离辐 射总剂量效应成为不可忽视的损伤因素。在 SiGe HBT 实现商业量产之后，针对 其的总剂量效应实验研究工作也随之展开，结果表明 SiGe HBT 抗总剂量效应能 力要强于传统 Si BJT，但早期研究的实验环节设计较为简单，多采用浮空辐照的 实验条件，对其辐照后的损伤机制仍采用传统 BJT 正向电学特性的方法进行分 析，不同氧化层中辐射诱发不同缺陷的影响也鲜有报道 [8][9][10][11][12] ；另一方面，由于总 剂量效应作用机理目前尚未形成统一的认识， 其计算机数值仿真并不像单粒子效 应一样具有完善的模型，基于数值仿真的 SiGe HBT 总剂量效应机理分析报道较 少 [13][14] [13][14][15][16] 与 SiNPN 双极晶体管相似，SiGe HBT 辐照后电学性能的退化主要是由基极…”

Total ionizing dose effects of domestic SiGe HBTs under different dose rates

“…However, the literatures [2] and [15] considered that because of the thin emitter-base (EB) spacer oxide and heavily doped base region of the SiGe HBTs, the leakage of the base current results from the interface traps that induced by the irradiation is suppressed, which results in an excellent performance of radiation-hardness of TID. And, strictly controlled process and special steps make sure that every hydrogen contaminants which are introduced in by the epitaxial Si growth are eliminated，bring about an immunity to ELDRS effects.…”

Angular dependence of proton-induced single event transient in silicon-germanium heterojunction bipolar transistors

“…Silicon-germanium heterojunction bipolar transistors (SiGe HBTs) are favored for space applications due to the superior low-temperature performance and the better tolerance to total ionizing dose and displacement damage than traditional silicon bipolar junction transistors (Si BJTs). [1][2][3][4][5][6] The siliconbased bandgap engineering provides a way to combine III-V performance with the yield and cost advantages of bulk silicon into an ideal platform. [7,8] However, SiGe HBTs are confirmed to be very sensitive to single event effect (SEE).…”