High breakdown voltage doubleδ-doping InGaP/InGaAs HFETs

• Main Authors: Yeong-Jia Chen, 陳永嘉
• Other Authors: Wei-Chou Hsu
• Format: Others
• Language: en_US
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/61878494949631972955

碩士 === 國立成功大學 === 電機工程學系 === 88 === In this thesis, the doubleδ-doping InGaP/InGaAs heterojuction field-effect transistors (HFET) have been successfully fabricated by low-pressure metalorganic chemical vapor deposition ( LP-MOCVD ) system. There is a large conduction band discontinuity (ΔEc) between InGaP and InGaAs and then the electrons in the channel would be confined well. Furthermore, InGaP has a wide bandgap (~1.92eV) and hence can be used to fabricate high breakdown voltage devices. High gate-to-drain breakdown voltage surpasses 60V in our studying structure. This high breakdown voltage is suitable for high power application. The maximal transconductance is 61mS/mm and the saturation drain current density is about 125mA/mm with a gate geometry 1.5´125 mm2 at 300K. The maximal extrinsic transconductance is 86mS/mm at 77K. In addition, the AlGaAs barrier layer creates an energy barrier in the conduction band to reduce electron injection into the buffer and we can obtain better pinch-off characteristic. The voltage gain as high as 71 was found. Therefore, the device has amplification capability