Interface Control of Perovskite High-dielectric-constant Film and Metal Electrode

钙钛矿高介电常数薄膜与金属电极的界面控制

• 批准号: 11555088
• 负责人: KIKKAWA Takamaro
• 金额: $ 8.77万
• 依托单位: HIROSHIMA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11555088/
• 关键词: barium; strontium; titanium; BST; energy band; band gap; inductively-coupled-plasma; sputtering; ペロブスカイト; 高誘電率; 集積回路; DRAM; キャパシタ; 電極; リーク電流; 高誘電率膜; 電極金属; チタン酸バリウム; チタン酸ストロンチウム; ULSI

This research was conducted for scaling of devices feature size such as capacitor and tlie performance improvement for future ULSI. In order to obtain sufficient effective dielectric constant, perovskite crystal structure barium strontium titanate (Ba,Sr)TiO_3 (BST) was investigated. Since BST is a dielctric material composed of 4 elements such as Ba, Sr, Ti and O, it is necessary to apply radio-frequency (RF) magnetron-plasma sputtering. In this research inducrtively-coupled-plasma(ICP) was applied to RF magnetron plasma. Properties of BST thin films, which were deposited by IGP-assisted RF magnetron-plasma sputtering, were investigated. It is found that the lCP-assisted RF-magnetron plasma improved the stoichiometry of the BST film. The energy band structure of the Ru/BST/Si system was investigated. It is found that the band gaps of BST and interface SiO_2 were investigated by XPS-EELS spectra and were determined as 4.30 eV and 8.95 eV, respectively. The valence band offsets for BST/Si and interface SiO_2/Si were measured by XPS and determined as 3.55 eV and 4.48 eV, respectively. Judging from the result, positive charges were trapped in the film so that the SiO_2 band was bent. The work function of Ru was 4.97 eV. Since the electron affinity was 3.57eV, the conduction band barrier height of Ru against BST was found to be 1.40 eV. Consequently, energy band structure of Ru/BST/SiO_2/Si was determined. Furthermore, electrical characteristics of BST film were investigated in terms of capacitance and leakage current. It is found that the leakage current characteristics were improved by 2 order of magnitude by introducing Ta thin interface layer deposition before BST depositiion.

这项研究是为了缩小器件的特征尺寸，如电容器和未来的ULSI的性能改善。为了获得足够的有效介电常数，研究了钙钛矿结构的钛酸锶钡（Ba，Sr）TiO_3（BST）。由于BST是由Ba、Sr、Ti和O等4种元素组成的介电材料，因此需要应用射频（RF）磁控等离子体溅射。本研究将电感耦合等离子体（ICP）应用于射频磁控等离子体。研究了用等离子体辅助磁控溅射法制备的BST薄膜的性能。结果发现，LCP辅助的RF磁控等离子体改善了BST薄膜的化学计量比。研究了Ru/BST/Si体系的能带结构。用XPS-EELS谱研究了BST和界面SiO_2的带隙，分别为4.30 eV和8.95 eV。用XPS测量了BST/Si和SiO_2/Si界面的价带偏移量，分别为3.55eV和4.48eV。结果表明，正电荷被捕获在薄膜中，使SiO_2带发生弯曲。Ru的功函数为4.97 eV。由于电子亲和势为3.57eV，Ru对BST的导带势垒高度为1.40 eV。从而确定了Ru/BST/SiO_2/Si的能带结构。此外，BST薄膜的电特性进行了研究，在电容和漏电流。结果表明，在BST淀积前引入Ta薄界面层淀积可使漏电流特性提高2个数量级。

项目成果

N.Fujiwara: "Inductively-coupled RF magnetron plasma physical vapor depoosition of BST"Abstract of Materials Research Society Fall Meeting Symposium CC. CC3,1. 164 (2000)

N.Fujiwara：“BST 的感应耦合射频磁控等离子体物理气相沉积”材料研究学会秋季会议研讨会摘要 CC。

T.Kikkawa: "Energy Band Structure of Ru/(Ba, Sr) TiO3/Si Capacitor Deposited by Inductively-Coupled Plasma-Assisted Radio-Frequency -Magnetron Plasma Sputtering"Applied Physics Letters. Vol.81, No.13. 2821-2823 (2002)

T.Kikkawa：“电感耦合等离子体辅助射频磁控管等离子体溅射沉积的 Ru/(Ba, Sr) TiO3/Si 电容器的能带结构”应用物理快报。

N. Fujiwara: "The Influence of Electrodes on the Characteristics of (Ba, Sr)TiO3"The Institute of Electronics of Information and Communication Engineers Technical Report SDM2001-52. 49-54 (2001)

N. Fujiwara：“电极对(Ba,Sr)TiO3特性的影响”信息通信工程师电子研究所技术报告SDM2001-52。

M. Yamato: "Influence of Si substrate crystal orientation on the properties of (Ba, Sr)TiO3"The Institute of Electronics of Information and Communication Engineers Technical Report. Vol.102, No.134. 43-47 (2002)

M. Yamato：“Si基板晶体取向对(Ba,Sr)TiO3性能的影响”信息通信工程师电子研究所技术报告。

藤原直憲: "(Ba, Sr) TiO3交誘電率膜特性の電極金属依存性"電子情報通信学会技術研究報告[シリコン材料・デバイス研究会]. SDM2001-52. 49-54 (2001)

Naonori Fujiwara：“(Ba, Sr) TiO3 交替介电常数薄膜特性取决于电极金属”IEICE 技术研究报告 [SDM2001-52 (2001)。