Development of wave form measurement method for high acuracy of detection time in semiconductor X-ray detector

半导体X射线探测器检测时间高精度波形测量方法的开发

• 批准号: 13650052
• 负责人: KIMURA Yoshihide
• 金额: $ 1.98万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13650052/
• 关键词: Coincidence Detection; Wave form measurement; Characteristic X-ray; Transmitted Electron; Transmission Electron Microscope; SDD X-ray detector; Trace elements mapping; Electron energy loss spectroscopy; コインシデンス; 透過型電子顕微鏡; 半導体X線検出器; 波形計測; 波形推定

The characteristics of materials and devices are considerably affected by trace elements such as impurity atoms localozed in semiconductor materials and the segregation of impurity atoms to the grain boundary on the nanometer scale. For this purpose, We developed a new analytical transmission electron microscope(TEM), called the coincidence TEM in 1995, which enabled elemental mapping by the coincidence measurement between the characteristic X-ray rand relevant energy-loss electrons. In the previous coincidence TEM system, a Si(Li) detector and a multi-anode position-sensitive phtomultiplier were attached to a TEM. Using these detectors, we succeeded in shorterning measurement time by selecting only specified energy-loss electrons after generating characteristic X-rays. The advanced coincidence TEM enabled to obtain an elemental mapping image in a shrter measurement rime, but no less than several hours was still needed for the coincidence measurement due to poor X-ray detection rime ac … More curacy of a Si(Li) detector. Minimizing the coincidence gate time delta t, which is a finite time window to determine whether X-rays and enemy-loss electrons are coincidentally detected, is one of the effective solutions to further reduce measurement time. in our previous works, the X ray detection time accuracy of a Si(Li) detector was still poor due to the use of an analog coincidence detection system and limits delta.-t to 100 nano second, although the performance of the high speed analog electronic circuit was satisfactoryIn the first year, we developed a off line type wave form measurement system which record the wave form of X-ray signal in every 10 nano second, and it result the accuracy of the detection time to 85 nano second. In the second year, we developed a DC rejection type pre-amplifier which reduce the noise level of the signal to 0.3mV Then we developed a 100MHz sampling system and coincidence selecting circuit with FPGA. Using these system, the accuracy of the detection time is reduced to 75 nano second. The limit of this inaccuracy is not due to the fluctuation of the rise time of the detection signal, but due to the noize of the detector. We suppose that the use of the low noise and the high speed detector like SDD (Silicon Drift Detector) reading more higher time accuracy Less

半导体材料中的杂质原子以及杂质原子在纳米尺度上向晶界的偏聚等微量元素对材料和器件的性能有很大的影响。为此，我们于1995年研制了一种新的分析透射电子显微镜（TEM），称为符合TEM，它通过特征X射线兰德相关能量损失电子之间的符合测量来实现元素映射。在以前的符合TEM系统中，一个Si（Li）探测器和一个多阳极位置敏感光电倍增管连接到TEM。使用这些探测器，我们成功地缩短了测量时间，只选择特定的能量损失电子产生特征X射线后。先进的符合透射电镜能在较短的测量时间内获得元素分布图像，但由于X射线探测时间差， ...更多信息 Si（Li）探测器的精度。最小化符合门时间Δ t是进一步减少测量时间的有效解决方案之一，所述符合门时间Δ t是确定X射线和敌方损失电子是否被符合地检测到的有限时间窗口。在我们以前的工作中，由于使用模拟符合探测系统和极限Δ，Si（Li）探测器的X射线探测时间精度仍然很差。100毫微秒，虽然高速模拟电路的性能不佳，但我们在第一年研制了一种离线式波形测量系统，每10毫微秒记录一次X射线信号的波形，使检测时间的精度达到85毫微秒。第二年，我们研制了直流抑制型前置放大器，将信号的噪声电平降低到0.3mV。然后，我们用FPGA研制了100MHz采样系统和符合选择电路。使用这些系统，检测时间的精度降低到75纳秒。这种误差的极限不是由于检测信号的上升时间的波动，而是由于检测器的噪声。我们认为，使用低噪声和高速检测器，如SDD（硅漂移检测器）阅读更高的时间精度更少