Study of Double Heterojunction Power Pseudomorphic High Electron Mobility Transistor

• Main Authors: Ying-Chern Shiau, 蕭應辰
• Other Authors: Yeong-Her Wang
• Format: Others
• Language: en_US
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/83791465686251673278

碩士 === 國立成功大學 === 電機工程學系 === 88 === One way of improving the AlGaAs/GaAs conventional HEMT performance is to use InGaAs as the two-dimensional electron gas channel material instead of GaAs. Because the InGaAs pseudomorphic channel is buried inside the double heterojunction layers, the processing techniques developed for AlGaAs/GaAs conventional HEMTs can be used for pseudomorphic HEMTs without modification. Gate recess is a important process during the fabrication of PHEMT device. For power applications, a recess opening larger than the gate is necessary to obtain a large BVgd. Our investigations showed that a BVgd as high as 25V can be achieved by simply making a wide recess in the AlGaAs schottcy layer. The wide recess device exhibited a peak gm of 151mS/mm, and a maximum current density of 248mA/mm. The narrow recess device exhibited a lower gate to drain breakdown voltage of 8.7 volts, a peak gm of 173mS/mm, and a maximum current density of 267mA/mm. Based on all experimental results, we find that wide recess device shows good potential in high-power and high-frequency performance. At last, we have successfully demonstrate the air-bridge technique with electroplating process. The air bridge technique will provides us applications to realize interconnect for MMIC (Monolithic Microwave Integrated Circuits) and high power devices.