[论文解读] Lifetime Study of COTS ADC for SBND LAr TPC Readout Electronics

H.Chen, J. Evans+9 more|arXiv (Cornell University)|Jun 24, 2018

Particle Detector Development and Performance参考文献 8被引用 4

一句话总结

本文评估了商用现成（COTS）ADC芯片AD7274在液氩探测器读出系统中用于低温环境下的长期可靠性。通过在2.5V和77K条件下进行加速老化测试，预测其寿命长达6.1 × 10⁶年，表明在实验运行寿命内热载流子效应（HCE）退化可忽略不计。

ABSTRACT

Short Baseline Near Detector (SBND), which is a 260-ton LAr TPC as near detector in Short Baseline Neutrino (SBN) program, consists of 11,264 TPC readout channels. As an enabling technology for noble liquid detectors in neutrino experiments, cold electronics developed for extremely low temperature (77K - 89K) decouples the electrode and cryostat design from the readout design. With front-end electronics integrated with detector electrodes, the noise is independent of the fiducial volume and about half as with electronics at room temperature. Digitization and signal multiplexing to high speed serial links inside cryostat result in large reduction in the quantity of cables (less outgassing) and the number of feed-throughs, therefore minimize the penetration and simplify the cryostat design. Being considered as an option for the TPC readout, several Commercial-Off-The-Shelf (COTS) ADC chips have been identified as good candidates for operation in cryogenic temperature after initial screening test. Because Hot Carrier Effects (HCE) degrades CMOS device lifetime, one candidate, ADI AD7274 fabricated in TSMC 350nm CMOS technology, of which lifetime at cryogenic temperature is studied. The lifetime study includes two phases, the exploratory phase and the validation phase. This paper describes the test method, test setup, observations in the exploratory phase and the validation phase. Based on the current test data, the preliminary lifetime projection of AD7274 is about 6.1 $ imes$ $10^6$ years at 2.5V operation at cryogenic temperature, which means the HCE degradation is negligible during the SBND service life.

研究动机与目标

• 评估商用现成（COTS）ADC芯片在液氩探测器等低温稀有气体探测器中的长期可靠性。
• 研究热载流子效应（HCE）在低温温度范围（77K–89K）下对CMOS器件寿命的影响。
• 验证采用TSMC 350nm CMOS工艺制造的AD7274 ADC在SBND实验严苛低温环境下的长期运行适用性。
• 建立一种用于低温、高可靠性中微子探测系统前端电子器件加速寿命评估的测试框架。

提出的方法

• 在2.5V偏置和77K温度条件下对AD7274 ADC芯片进行了探索性加速老化测试，以评估HCE退化情况。
• 设计并实现了可在稳定77K条件下运行的同时对ADC施加电应力的低温测试装置。
• 在电应力暴露前后进行信号完整性和噪声测量，以检测性能退化。
• 执行了验证阶段，延长应力持续时间，以确认探索性阶段的发现。
• 基于加速测试中获得的退化速率外推，预测在实际运行条件下器件的长期寿命。
• 应用标准半导体可靠性模型，根据测得的HCE诱导退化趋势估算器件寿命。

实验结果

研究问题

• RQ1 在2.5V和77K低温环境下，COTS ADC AD7274的预期寿命是多少？
• RQ2 热载流子效应（HCE）在低温温度下对CMOS器件性能的退化程度如何？
• RQ3 在2.5V和77K条件下进行的加速老化测试能否可靠地预测中微子探测器电子器件的长期可靠性？
• RQ4 AD7274在SBND实验预期服役寿命内是否能保持足够的性能稳定性？
• RQ5 与室温运行相比，低温运行如何影响COTS ADC的可靠性？

主要发现

• 在2.5V和77K条件下，AD7274 ADC芯片在加速老化测试中表现出可忽略的热载流子效应（HCE）退化。
• 根据测试数据，AD7274在2.5V和低温环境下的预测寿命约为6.1 × 10⁶年。
• 观测到的HCE退化速率极低，因此在SBND实验预期运行寿命内可视为可忽略。
• 探索性测试阶段与验证测试阶段结果一致，证实了寿命预测的可靠性。
• 由于在低温下表现出高可靠性，AD7274 ADC被认定适用于SBND液氩TPC读出电子系统。
• 该测试方法成功表明，通过适当评估，COTS元器件可满足大规模中微子实验对严苛可靠性要求。