金屬(鋁)/鐵電薄膜(鋯鈦酸鉛)/絕緣層(氧化鉿與氧化鋯)/矽 結構電容與場效電晶體之製作及電性分析

The Fabrication and Electrical Properties of Metal(Al)/Ferroelectric(Pb(Zr0.6Ti0.4)O3)/Insulator(HfO2 and ZrO2)/Silicon (p-type) MFIS Capacitors and Field Effect Transistors

江政達(Jheng-Da Jiang)

指導教授 ： 李雅明

國立清華大學/電機資訊學院/電子工程研究所/碩士(2006年)

https://doi.org/10.6843/NTHU.2006.00211

摘要

在本實驗中我們成功的製作出了金屬(Al)/鐵電薄膜（PZT）/絕緣層/半導體（p-type）電容器及場效電晶體。絕緣層採用HfO2與ZrO2兩種高介電常數材料，以射頻磁控濺鍍法沈積不同厚度的絕緣層當作緩衝層，經過500oC一分鐘的熱退火處理後，再以射頻磁控濺鍍法沈積PZT，並給予400oC、500oC、600oC與700oC四種不同溫度的熱退火處理。自發性極化的特性是鐵電材料應用於非揮發性記憶體的主要精神，故本實驗主要是藉由電容-電壓以及電流-電壓的量測探討鐵電材料在其中所扮演的角色。
在電容的量測方面，我們發現在PZT經過500oC的熱退火處理可以得到較大的記憶窗，由HfO2當絕緣層的最大的記憶窗達到3.97V，而由ZrO2當絕緣層的最大記憶窗達到3.04V。我們可發現C-V曲線一開始受鐵電極化主導呈現順時針走向，而隨著掃瞄電壓越加越大，電荷注入的影響大於鐵電極化，因此C-V曲線呈現由電荷注入所主導的逆時針走向。在電晶體的量測方面，同樣在PZT經過500oC的熱退火處理可以得到較大的記憶窗。以HfO2當絕緣層的電晶體其次臨界斜率為286mV/decade以及電子遷移率為86cm2/V-sec，已顯現出本電晶體的基本特性，其記憶保持力可達到11.6天，顯示出在記憶保持力部分得到不錯的結果。

關鍵字

鐵電

並列摘要

Ferroelectric field effect transistors with a metal-ferroelectric- insulator-silicon (MFIS) structure have emerged as promising nonvolatile memory devices. In this work, metal (Al)/ferroelectric (PZT)/insulator/Si MFIS capacitors and field effect transistors using hafnium oxide (HfO2) and zirconium oxide (ZrO2) insulator layers were fabricated. After deposition, the HfO2 and ZrO2 insulator films were first annealed at 500oC and the PZT films were annealed at different temperatures of 400oC, 500oC, 600oC and 700oC. The variation of the memory window as a function of annealing temperature was studied. The maximum capacitance-voltage (C-V) memory window of Al/PZT/HfO2/p-Si capacitors with 500oC-annealed PZT was 3.97V at a sweep voltage of 8V and the similar value for Al/PZT/ZrO2/p-Si capacitors was 3.04V at a sweep voltage of 12V.
The MFIS field effect transistors show normal IDS-VDS and IDS-VGS characteristics. The subthreshold slope of Al/PZT/HfO2/p-Si transistors is 286 mV/decade and the electron mobility is 86 cm2/V-sec. The MFIS transistors with ZrO2 insulator layer show poorer performances. The retention property of MFIS field effect transistors was also measured. The fabricated n-channel MFIS field effect transistors with Al/PZT/HfO2/Si structure exhibited a memory window larger than 0.5V after 11.6 days.

參考文獻

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