Analysis and Control of Ferroelectric/Semiconductor (Metal) Interface for Their Device-Application

铁电/半导体（金属）接口的分析和控制及其器件应用

• 批准号: 12650348
• 负责人: NIU Hirohiko
• 金额: $ 1.98万
• 依托单位: Himeji Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12650348/
• 关键词: Ferroelectric gate FET; MFIS structure; PZT thin film; A1_2O_3 thin film; MFS device; PFM observations; MOCVD; TiO_2 thin film; MFS型デバイス; 強誘電性のAFM観察; MOCVD法

Metal Ferroelectric Insulator Semiconductor (MFIS) structures made on silicon substrate have been studied. The MFIS structures composed of the PZT F-layer fabricated by MOCVD and the buffer I-layer which is among films of MgO by RF sputter, A1_2O_3 by plasma-oxidation and TiO_2 by MOCVD were examined. The important knowledge derived from this study can be summarized as follows.1. Capacitance-voltage (C-V) characteristics of the MFIS diodes with the buffer I-layer of sputtered MgO or plasma-oxidized A1_2O_3 exhibited hysteresis curves due to the ferroelectricity of PZT, namely, C-V memory-windows (of narrow width less than 1V). In respect of the PZT film's crystallinity, the MFIS with MgO was better than that with A1_2O_3, whereas speaking of the I/S interface the former's interface state-density (lO^<12>eV^-1cm^-2 mesured by DLTS) was ten times as large as the latter's.2. The C-V memory-windows observed in the MFIS diode with the MOCVD-TiO_2 was excellent in shape and of wide width more than 2V.3. All the memory-windows observed in the three kinds of MFIS diodes were remarkably different in shape and width from the ideal one culculated by assuming neither of leakage current and interface state, and also showed the decrease in width due to carrier injection; this suggests that it becomes a critical issue to reduce the voltage across the I-layer when the memory-window opens.4. Polarization switching processes in epitaxial PZT thin films grown on SrRuO_3(100) were observed by means of piezoresponse scanning force microscopy. It was foud that during switching period the new nucleations were induced in the PZT film with Pt top electrode.5. Perovskite PZT films were successfully grown at 395 ℃ on Pt/SiO_2/Si by MOCVD ; they showed D-Ehysteresis of which ramanense is sufficient for the MFIS-FET memory to operate.

对硅衬底金属铁电绝缘半导体(MFIS)结构进行了研究。研究了由MOCVD法制备的PZT F层、射频溅射制备的MgO薄膜、等离子体氧化制备的Al_2O_3薄膜和MOCVD制备的TiO_2薄膜中的缓冲I层构成的微细结构。从这项研究中获得的重要知识可以概括如下。由于PZT的铁电性，以溅射的氧化镁和等离子体氧化的Al_2O_3为缓冲I层的MFIS二极管的电容-电压(C-V)特性表现出滞后曲线，即C-V存储窗口(宽度小于1V)。在PZT薄膜的结晶度方面，添加氧化镁的PZT薄膜的结晶度要好于添加Al_2O_3的PZT薄膜，而对于I/S界面，前者的界面态密度(Lo^&lt；12&gt；ev^-1 cm^-2)是后者的十倍。在MOCVD-TiO2MFIS二极管中观察到的C-V记忆窗口形状优良，宽度大于2V.3。在三种MFIS二极管中观察到的所有记忆窗口在形状和宽度上都与假设漏电流和界面态都不同的理想记忆窗口有显著不同，并且还显示出由于载流子注入而导致的宽度减小，这表明当记忆窗口打开时，降低I层的电压成为一个关键问题。用压电响应扫描力显微镜观察了在SrRuO_3(100)衬底上生长的PZT外延薄膜的极化转换过程。研究发现，在切换过程中，以铂为顶电极的PZT薄膜中出现了新的形核现象。用MOCVD方法在395℃的温度下在Pt/SiO_2/Si衬底上成功地生长了钙钛矿型PZT薄膜，其磁滞特性足以满足MFIS-FET存储器的工作要求。

项目成果

M.Shimizu et al.: "Preparation of Ir-Based Thin Film Electrodes by MOCVD"Proceedings of the 12th IEEE International Symposium on the Applications of Ferroelectrics. (印刷中).

M. Shimizu 等人：“通过 MOCVD 制备 Ir 基薄膜电极”第 12 届 IEEE 国际铁电体应用研讨会论文集（正在出版）。

Masaru Shimizu, Hironori Fujisawa, Hirohiko Niu et al: "MOCVD of Ir and IrO_2 Thin Films for PZT Capacitors"Materials Research Society Symposium Proceedings. 655. CC10.4.1-6 (2001)

Masaru Shimizu、Hironori Fujisawa、Hirohiko Niu 等：“MOCVD of Ir and IrO_2 Thin Films for PZT Capacitors”材料研究会研讨会论文集。

M.Okaniwa et al.: "Low Temperature MOCVD of Pb(Zr, Ti)O_3 Thin Films Using Seeds"Ext.Abs.of 1st Int.Meeting on Ferroelectric Random Access Memories. FED-175. 91-92 (2001)

M.Okaniwa 等人：“使用种子的 Pb(Zr, Ti)O_3 薄膜的低温 MOCVD”Ext.Abs.of 1st Int.Meeting on Ferroelectric Random Access Memories。

H.Fujisawa et al.: "Observations of Initial Growth Stage of Epitaxial Pb(Zr, Ti)O_3 Thin Films on SrTiO_3(100) Substrate by MOCVD"Journal of Crystal Growth. (印刷中). (2002)

H. Fujisawa 等人：“通过 MOCVD 在 SrTiO_3(100) 基板上外延 Pb(Zr, Ti)O_3 薄膜的初始生长阶段的观察”《晶体生长杂志》(2002 年)。

H.Fujisawa et al.: "Observations of Initial Growth Stage of Epitaxial Pb(Zr,Ti)O_3 Thin Films on SrTiO_3(100) Substrate by MOCVD"Journal of Crystal Growth. (印刷中). (2002)

H. Fujisawa 等人：“通过 MOCVD 在 SrTiO_3(100) 基底上外延 Pb(Zr,Ti)O_3 薄膜的初始生长阶段的观察”(Journal of Crystal Growth) (2002 年出版)。