Title :
Q-factor characterization of RF GaN-based metal-semiconductor-metal planar interdigitated varactor
Author :
Chu, Chun San ; Zhou, Yugang ; Chen, Kevin J. ; Lau, Kei May
Author_Institution :
Dept. of Electr. & Electron. Eng., Hong Kong Univ. of Sci. & Technol., China
fDate :
7/1/2005 12:00:00 AM
Abstract :
We report the characterization of quality (Q)-factor of RF metal-semiconductor-metal (MSM) planar interdigitated varactors fabricated by standard AlGaN/GaN HEMT process. The MSM varactors have wide tuning range and exhibit high quality-factor at both the maximum and minimum capacitance values. The fundamental limitation of the Q-factor in the medium capacitance range is also revealed. The elimination of ohmic contact resistance in the MSM varactor configuration pushed up the peak Q-factor to 92 at 0.5 GHz and 41 at 1.1 GHz. The operation of the MSM varactor is modeled by a physical equivalent circuit, with which the dependence of the Q-factor over the entire tuning voltage range can be explained.
Keywords :
III-V semiconductors; Q-factor; Schottky barriers; aluminium compounds; equivalent circuits; gallium compounds; high electron mobility transistors; metal-semiconductor-metal structures; semiconductor device models; varactors; wide band gap semiconductors; 0.5 GHz; 1.1 GHz; AlGaN-GaN; MSM varactor configuration; Q-factor characterization; RF planar interdigitated varactor; Schottky contacts; metal-semiconductor-metal varactor; ohmic contact resistance; physical equivalent circuit; Aluminum gallium nitride; Capacitance; Contact resistance; Equivalent circuits; Gallium nitride; HEMTs; Ohmic contacts; Q factor; Radio frequency; Varactors; AlGaN/GaN; Schottky contacts; capacitance–voltage (; equivalent circuit; varactor;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2005.851181
