Influence of Sinking-Gate on Al_(0.24)Ga_(0.76)As/In_(0.22)Ga_(0.78)As Double Heterojunction High Electron Mobility Transistors

摘要

The influence of gate metal with thermal annealed process adopt to control the distance between gate and channel on pseudomorphic Al_(0.24)Ga_(0.76)As/ In_(0.22)Ga_(0.78)As double heterojunction high electron mobility transistors (DH-HEMTs) were studied. Compared to device with gate-recess process, the distance of gate-to-channel could be controlled through the thermal annealed process and therefore exhibit a lower series resistance. Measured transconductance of 150 mS/mm and an open-drain voltage gain of 136 for the DH-HEMT with an as deposited gate are enhanced to 175 mS/mm and 160 for the DH-HEMT with a 330-°C annealed gate. Good device linearity is also obtained with a low second-harmonic to fundamental ratio of 3.55 %. In addition, good microwave performances such as unit-current gain- and maximum power gain- frequency were also obtained from devices with gate-annealed process.