Ka-Band GaN HEMT With Segmented Discrete Field Plate

An innovative segmented discrete field plate (SDFP) was applied in the Ka-band GaN high-electron-mobility transistor (HEMT). The device was located at the top and bottom of gate area but disconnected from any electrode. The new device with SDFP got an <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small>-state breakdown voltage of 131 V, while the breakdown voltage of ordinary T-gate devices was 98 V with source-drain spacing at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2.4~\mu $</tex-math> </inline-formula>m. In addition, the method also achieved an order of magnitude lower <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small>-state leakage current and good suppression of current collapse than the T-gate device. In particular, a device of SDFP achieved an output power of 6.08 W/mm, a gain of 9.6 dB, and a power added efficiency of more than 33%. This technique held the potential for application in Ka-band high opreating voltage GaN HEMTs.