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

Volume

26

Issue

7

fYear

2005

fDate

7/1/2005 12:00:00 AM

Firstpage

432

Lastpage

434

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;

fLanguage

English

Journal_Title

Electron Device Letters, IEEE

Publisher

ieee

ISSN

0741-3106

Type

jour

DOI

10.1109/LED.2005.851181

Filename

1458947