Proposal of varialbe-area electrode structure by field effect and its application to variable capacitors

2014 Fiscal Year Final Research Report

• Project/Area Number: 24360119
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Electronic materials/Electric materials
• Research Institution: Japan Advanced Institute of Science and Technology
• Principal Investigator: TOKUMITSU Eisuke 北陸先端科学技術大学院大学, グリーンデバイス研究センター, 教授 (10197882)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 薄膜トランジスタ / 可変容量キャパシタ / 強誘電体 / 高誘電率材料 / 酸化物半導体

Outline of Final Research Achievements

Objective of this research is to develop a new variable capacitance element, using oxide conductors and ferroelectric or high-dielectric constant materials which can induce large charge density. Such a large charge density enables us to switch on and off the oxide conducting thin film by the gate voltage, which leads to variable-area electrode and variable capacitance. In this project, at first, fabrication conditions of ferroelectric (Bi,La)4Ti3O12 (BLT) film were optimized and new high-dielectric constant materials were searched by solution process. Next, thin film transistor structure was fabricated using ITO or In2O3 channel to realize variable capacitance elements. It is confirmed that the source-gate capacitance can be changed by the gate voltage with a capacitance ratio of 1500%. Switching properties were also characterized. In addition, scaling down the device size was achieved using nanoimprint technology.

Free Research Field

固体電子工学