Fabrication and Characterization of Pt/(Bi, La)4Ti3O12/Si3N4/Si Metal Ferroelectric Insulator Semiconductor Structure for FET-Type Ferroelectric Memory Applications
Fabrication and Characterization of Pt/(Bi, La)4Ti3O12/Si3N4/Si Metal Ferroelectric Insulator Semiconductor Structure for FET-Type Ferroelectric Memory Applications
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用于 FET 型铁电存储器应用的 Pt/(Bi, La)4Ti3O12/Si3N4/Si 金属铁电绝缘体半导体结构的制造和表征
DOI：
10.1143/jjap.40.2977
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
H. Ishiwara
中科院分区：
文献类型：
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作者：
T. Kijima;Y. Fujisaki;H. Ishiwara
对于场效应晶体管(FET)型铁电存储器，研究了c轴取向的(Bi，La)4Ti3O12薄膜，其剩余极化Pr为4µC/cm2。采用溶胶-凝胶法在Si衬底上用原子氮自由基制备了非晶态Si3N4薄膜，制备了Bi3.25La0.75Ti3O12薄膜。结果表明，用化学计量比的Sol-Gel溶液制备的薄膜即使在800℃氧气气氛中也没有晶化。因此，采用2.5%~7.5%的过量铋溶液，并优化了预退火温度、晶化温度、膜厚和晶化环境等参数。结果表明，在600°C以上的温度下，制备的Bi3.25La0.75Ti3O12薄膜具有良好的c轴择优取向，具有良好的结晶度和表面形貌。在铂/100 nm-Bi3.25La0.75Ti3O12/3 nm-Si3N4/Si(金属/铁电/绝缘体/半导体)结构中，C-V特性表现出一个约1V的存储窗口的磁滞回线，在零偏压下保持的高、低电容值均不超过3h。
For field effect transistor (FET)-type ferroelectric memories, c-axis oriented (Bi, La)4Ti3O12 films with small remanent polarization Pr of 4 µC/cm2 were investigated. Bi3.25La0.75Ti3O12 films were prepared by the sol-gel method on amorphous Si3N4 layers formed on Si substrates using atomic nitrogen radicals. It was found that the films formed using stoichiometric sol-gel solution did not crystallize even after annealing at 800°C in O2 ambient. Therefore, 2.5 to 7.5% excess-Bi solutions were used and such parameters as pre annealing and crystallization temperatures, film thickness and crystallization ambient were optimized. As a result, the well c-axis-oriented Bi3.25La0.75Ti3O12 films with good crystallinity and good surface morphology were obtained at temperatures higher than 600°C. It was also found in a Pt/100 nm-Bi3.25La0.75Ti3O12/3 nm-Si3N4/Si (metal/ferroelectric/insulator/semiconductor) structure that C–V characteristics showed a hysteresis loop with a memory window of about 1 V and both high and low capacitance values kept at zero bias voltage did not change for more than 3 h.