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

基本信息

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

项目摘要

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.

这项研究是针对设备的缩放尺寸进行的，例如电容器和未来ULSI的性能改进。为了获得足够的有效介电常数，研究了钙钛矿晶体结构钛钛酸氨基钛盐（BA，SR）TIO_3（BST）。由于BST是由BA，SR，Ti和O等4个元素组成的二元材料，因此有必要施加射频（RF）Magnetron-plasma-plasma溅射。在这项研究中，将诱导耦合的血压（ICP）应用于RF磁铁等离子体。研究了由IGP辅助的RF磁控蛋白血浆溅射沉积的BST薄膜的性质。发现由LCP辅助的RF-MAGNETRON等离子体改善了BST膜的化学计量。研究了RU/BST/SI系统的能量带结构。发现BST和界面SIO_2的频带间隙分别测定为4.30 eV和8.95 eV。通过XPS测量BST/SI和界面SIO_2/SI的价频段偏移，并分别确定为3.55 eV和4.48 eV。从结果来看，阳性电荷被困在电影中，以使SIO_2频段弯曲。 RU的工作功能为4.97 eV。由于电子亲和力为3.57EV，因此发现RU对BST的传导带屏障高度为1.40 eV。因此，确定了RU/BST/SIO_2/SI的能带结构。此外，还研究了BST膜的电气特性，以电容和泄漏电流。发现通过在BST沉积前引入TA薄界面层沉积，通过2个数量级提高了泄漏电流特性。