本研究針對 HfO2 基鐵電場效電晶體（FeFET）於低溫環境下之鐵電切換（ferroelectric switching）與電荷去捕獲（detrapping）機制進行研究，探討 300 K 至 8 K 溫度範圍內之元件特性變化，並比較兩種物理機制之活化能差異。研究元件採用具有 0.4 nm SiO2 介面層之 HfO2 基 FeFET，以分析介面層對元件切換與可靠度之影響。
本研究利用 Positive-Up-Negative-Down（PUND）量測分析鐵電極化切換行為，並透過 Fast-IV 量測觀察臨界電壓隨時間之鬆弛特性，以分別萃取鐵電切換時間與電荷去捕獲時間常數。進一步利用 Arrhenius 分析建立溫度與時間常數之關係，計算鐵電切換活化能與電荷去捕獲活化能，並比較不同溫度區間之載子傳輸與極化切換機制。
實驗結果顯示，鐵電切換與電荷去捕獲皆具有明顯的溫度相依性。鐵電切換活化能顯示低溫下極化切換更容易發生，而電荷去捕獲活化能則反映高溫與低溫區間具有不同的載子釋放機制。透過比較兩種活化能，可進一步釐清 FeFET 中鐵電極化與電荷陷阱之物理機制，並提供 HfO2 基 FeFET 於低溫記憶體及低功耗運算應用之設計與可靠度分析依據。

Ferroelectric field-effect transistors (FeFETs) based on HfO2 have emerged as promising candidates for next-generation non-volatile memory due to their compatibility with CMOS technology, low power consumption, fast switching speed, and potential for in-memory computing applications. However, the physical mechanisms governing ferroelectric polarization switching and charge detrapping under cryogenic operation remain insufficiently understood, limiting the optimization of device reliability and performance.
In this work, the temperature-dependent switching and detrapping characteristics of HfO2-based FeFETs with an ultra-thin 0.4 nm SiO2 interfacial layer were systematically investigated over a temperature range from 300 K to 8 K. Polarization switching behavior was characterized using the Positive-Up-Negative-Down (PUND) measurement technique, while charge detrapping was analyzed through fast current-voltage (Fast-IV) measurements. The characteristic switching time and detrapping time were extracted from the experimental data, and the corresponding activation energies were determined using Arrhenius analysis.
The experimental results show that both polarization switching and charge detrapping exhibit pronounced temperature dependence. The extracted switching activation energy indicates that polarization reversal becomes more favorable at lower temperatures, whereas the detrapping activation energy reveals different carrier emission mechanisms in the high- and cryogenic-temperature regions. Furthermore, a comparison between the switching and detrapping activation energies provides insight into the distinct physical processes governing ferroelectric domain dynamics and charge trapping behavior. These findings improve the understanding of low-temperature operation in HfO2-based FeFETs and provide valuable guidelines for the design and optimization of reliable ferroelectric memory devices for future low-power and cryogenic computing applications.

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