Enhancement-Mode AlGaN/GaN Metal-Oxide-Semiconductor High Electron Mobility Transistors by Fluorine Plasma Treatment

• Main Authors: Che-YuanChang, 張哲源
• Other Authors: Yeong-Her Wang
• Format: Others
• Language: en_US
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/k999c6

碩士 === 國立成功大學 === 微電子工程研究所 === 103 === In this study, we have successively fabricated the enhancement-mode AlGaN/GaN HEMTs by fluorine plasma treatment techniques. The conduction band at the AlGaN/GaN interface is raised above the Fermi level as a result of the negatively charged fluorine ions incorporated in AlGaN layer. Therefore, the threshold voltage is effectively improved to 0.3 V. The maximum drain current and maximum transconductance are 522 mA/mm and 127 mS/mm, respectively. Besides, a low temperature and low fabrication difficulty liquid-phase deposition (LPD) is utilized to deposit a high dielectric constant thin film of ZrO2. The metal-oxide-semiconductor HEMT with ZrO2 thin film is also fabricated, which can solve the issues caused by the recess procedure, such as higher gate leakage current and lower breakdown voltage. In order to analysis the chemical composition, crystal phase, surface roughness, and thickness of the LPD-ZrO2 thin film, (1) Electron Spectroscopy for Chemical Analysis (2) X-Ray Diffractometer (3) Atomic Force Microscopy , (4) Transmission Electron Microscopy are adopted in this research. The gate leakage current can be effectively suppressed at 6.96 × 10-5 A/mm, and the three-terminal breakdown voltage is increased to 90 V. The high-frequency characteristics and low-frequency noise are also improved.