AI 中文总结
该研究突破CZT半导体加工温度限制，采用250℃原子层沉积Al₂O₃钝化，使CZT探测器暗电流降5倍、像素间漏电流降近一个数量级，提升性能且兼容加工，助力高性能X射线成像系统开发。
AI 中文摘要
与普遍认为的将碲锌镉（CZT）半导体在150℃以上加工会导致器件不可逆退化的观点相反，本文表明，采用原子层沉积（atomic layer deposition）在250℃沉积的Al₂O₃钝化层不仅能保留CZT探测器的性能，还能显著提升其性能。对像素化的金属-半导体（MS）和金属-绝缘体-半导体（MIS）CZT探测器，采用薄原子层沉积Al₂O₃膜进行钝化并开展电学表征。钝化后的器件即便在1000V的高偏置操作下也未出现可测量的退化，反而暗电流降低了约5倍，而像素间漏电流在-200V下从约41nA降至约2-3nA，降低了近一个数量级。钝化还使相邻像素的暗电流特性高度均匀，并完全消除了电流-电压滞后现象，表明缺陷辅助的电荷输运得到了抑制。此外，钝化后MS和MIS探测器的暗电流未观察到显著差异，说明Al₂O₃层主导了表面电学行为。这些结果表明，250℃下优化的Al₂O₃钝化与高性能CZT探测器加工完全兼容，为实现更低噪声、更高光谱分辨率的X射线成像系统提供了实用途径。
英文摘要
Contrary to the prevailing view that processing cadmium zinc telluride (CZT) semiconductors above 150 °C leads to irreversible device degradation, here we show that Al2O3 passivation layer deposited by atomic layer deposition at 250 °C not only preserves CZT detector performance but also substantially improves it. Pixelated metal-semiconductor (MS) and metal-insulator-semiconductor (MIS) CZT detectors were passivated with a thin atomic-layer-deposited Al2O3 film and characterized electrically. The passivated devices exhibited no measurable degradation, even under a high-bias operation of 1000 V. Instead, the dark current decreased by approximately a factor of five, while the interpixel leakage current was reduced by nearly one order of magnitude, from ~41 nA to ~2-3 nA at -200 V. Passivation also produced highly uniform dark-current characteristics across adjacent pixels and completely eliminated current-voltage hysteresis, indicating suppression of defect-assisted charge transport. Furthermore, no significant difference in dark current was observed between the MS and MIS detectors after passivation, suggesting that the Al2O3 layer dominates the surface electrical behavior. These results demonstrate that optimized Al2O3 passivation at 250 °C is fully compatible with high-performance CZT detector processing and provides a practical route toward lower-noise, higher-spectral-resolution X-ray imaging systems.
Comments18 pages, 10 figures, including supplementary material
