The electrical properties of barium strontium titanate (Ba,Sr)TiO3 thin film capacitor and Metal-(Ba,Sr)TiO3-Semiconductor Field Effect Transistors

• Main Authors: Yu-Rung Liu, 劉育榮
• Other Authors: Joseph Ya-Min Lee
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/75662932271929339177

碩士 === 國立清華大學 === 電子工程研究所 === 89 === In this work , the electrical characteristics of Au/BST/Silicon(P-type) (MIS) capacitors and n-channel metal gate metal-oxide-semiconductor field effect transistors (MOSFET) with (BaxSr1-x)TiO3(BST) gate dielectric are investigated. The BST thin films are deposited by magnetron control RF sputtering. The perovskite phase was confirmed by X-Ray Diffraction spectra. The dielectric constant of 140nm thick BST thin film is around 70~80 at 100kHz and decreases with increasing frequency. The leakage current is around 10-7 A/cm2 in the range of 0~3 V and increases rapidly with increasing temperature. The I-V and C-V characteristics of MIS capacitors are discussed. The conduction current mechanism of BST films at different temperatures is studied. For MIS structure, Poole-Frenkel is dominant in the room temperature, when the device is negative biased (operated in accumulation region). The IDS-VDS and IDS—VGS characteristics are measured from MOSFET with BST gate dielectric. The electron mobility obtained from gm versus VG plot was about 206 cm2/V·s. The subthreshold swing was 136.7 mV/dec. The interface density, surface recombination velocity and the minority carrier lifetime measured from gated diodes. Comparison with conventional MOSFETs with SiO2 gate oxide was made.