Performance evaluation of a new 30 µm thick GaAs x-ray detector grown by MBE
Performance evaluation of a new 30 µm thick GaAs x-ray detector grown by MBE
复制标题
MBE 生长的新型 30 µm 厚 GaAs X 射线探测器的性能评估
DOI：
10.1088/2053-1591/abe73c
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发表时间：
2021
影响因子：
2.3
通讯作者：
Lioliou G
中科院分区：
文献类型：
--
作者：
Lioliou G
研究了直径为400μm、I层厚度为30μm的圆形台面GaAsp+-In+光电二极管在20℃下作为光子计数X射线能谱探测器的性能。早些时候使用不同制造工艺和同一外延片不同区域的材料制作的MBE探测器被证明存在以下问题：高温下相对较高的泄漏电流；限制其耗尽层宽度的高有效载流子浓度；以及材料缺陷(蝴蝶缺陷)[Lioliou等人2019 Nucl。Instrum。方法物理实验。决议A 946 162670]。然而，新的探测器具有更好的性能(较低的漏电流和I层内的有效载流子浓度)。使用新的探测器和低噪声读出电子器件，在20℃下，在5.9keV时，能量分辨率达到750 eV±20 eV半高全宽(FWHM)，与由金属有机气相外延生长的高质量材料制成的高质量GaAs探测器的能量分辨率相当[Lioliou等人2017年应用。太棒了。244506)。结果表明，当晶片质量不一致时，由相同的外延片制成的探测器的性能有很大的不同，以及不同制造工艺的影响。
A circular mesa (400 μm diameter) GaAs p+-in+ photodiode with a 30 μm thick i layer was characterized for its performance as a detector in photon counting x-ray spectroscopy at 20 C. The detector was fabricated from material grown by molecular beam epitaxy (MBE). An earlier MBE-grown detector fabricated using a different fabrication process and material from a different area of the same epiwafer was shown to suffer from: relatively high leakage current at high temperatures; a high effective carrier concentration that limited its depletion layer width; and material imperfections (butterfly defects)[Lioliou et al 2019 Nucl. Instrum. Methods Phys. Res. A 946 162670]. However, the new detector has better performance (lower leakage current and effective carrier concentration within the i layer). Using the new detector and low noise readout electronics, an energy resolution of 750 eV±20 eV Full Width at Half Maximum (FWHM) at 5.9 keV was achieved at 20 C, equal to that reported for high quality GaAs detectors made from high quality material grown by metalorganic vapour phase epitaxy [Lioliou et al 2017 J. Appl. Phys. 122 244506]. The results highlight the substantially different performances of detectors made from the same epiwafer when the wafer qualities are not uniform and the effects of different fabrication processes.