An InGaP/InGaAs PHEMT with High IP3 for Low Noise Application

• Main Authors: Guan-Ji Chen, 陳冠吉
• Other Authors: Edward Y. Chang
• Format: Others
• Language: en_US
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/95451966093024371324

碩士 === 國立交通大學 === 材料科學與工程系 === 91 === The purpose of this dissertation is to develop the high linearity and low noise high electron mobility transistors for wireless application. The device structure design has the following features: First, high band-gap InGaP material was used as the Schottky layer to reduce the leakage current and noise figure of the devices. Second, AlGaAs was used as the spacer layer to increase the device electron mobility. Third, two Si δ-doped layers above and below the InGaAs channel region in the structure were used to increase the uniformity of the distribution of the electric current, and improve the linearity of the devices. In this study, the InGaP/InGaAs PHEMT developed with gate length of 0.25μm and gate width of 160μm had the following DC characteristics: Idss=240 mA/mm, gm=414.2 mS/mm, pich-off voltage=-0.8V, and gate-to-drain breakdown voltage BVgd=15.6V. The devices also demonstrated good RF characteristics with fT=70 GHz, and fmax=210 GHz. The devices also exhibited excellent low noise characteristics. The 160μm HEMT had a noise figure of 0.45dB at 12 GHz, and demonstrated high linearity characteristics. The OIP3 and the IIP3 at 6 GHz and bias at Vds=2.4V were 28.1 dBm and 7 dBm, respectively. From the results of the RF measurement, the PHEMT developed is a high-frequency low noise device with excellent high linearity and is applicable for high frequency wireless applications.