1999 Fiscal Year Final Research Report Summary
The influence of thin film fabrication process on ferroelectric properties and ferroelectric random access memories
| Project/Area Number |
10450120
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Electronic materials/Electric materials
|
|---|
| Research Institution | Nara Institute of Science and Technology |
|---|
Principal Investigator |
SHIOSAKI Tadashi Nara Institute of Science and Technology, Graduate School of Material Science, 物質創成科学研究科, 教授 (80026153)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
NISHIDA Takashi Nara Institute of Science and Technology, Graduate School of Material Science, 物質創成科学研究科, 助手 (80314540)
HORIUCHI Toshihisa Kyoto University, Faculty of Engineering, 大学院・工学研究科, 助手 (10238785)
OKAMURA Souishirou Nara Institute of Science and Technology, Graduate School of Material Science, 物質創成科学研究科, 助教授 (60224060)
|
|---|
| Project Period (FY) |
1998 – 1999
|
| Keywords | Ferroelectric Thin Film / FRAM / MOCVD / Chemical Solution Deposition / Electron-Beam-Induced Reaction / Thermally Stimulated Current / Polarization Fatigue / Imprint |
|---|
| Research Abstract |
Ferroelectric thin films have been interesting materials because of FeRAM application. Therefore, ferroelectric thin films are fabricated by various preparation methods. However, the ferroelectric thin films obtained shows the peculiar properties such as the polarization fatigue, imprint and so on. We studied these phenomena, and obtained the knowledge about them.
The thermally stimulated current (TSC) of the this films were examined. The peak of TSC of fatigued sample are obtained, revealing that the main origin of the polarization fatigue phenomena was the domain pinning caused by trapped charge carriers injected by polarization reversal. The internal bias field in the films were also investigated by pulse measurement. The PZT thin films obtained by a chemical solution deposition process exhibited a conspicuous initial voltage shift in the D-E hysteresis loop toward the negative-bias field. It was concluded that the origin of the voltage shift was an internal bias field due to asymmetric space-charge distribution induced by the natural alignment of spontaneous polarization during the cooling process. The internal bias field caused asymmetric depolarization at the zero-bias field.
|
