Eur. Phys. J. Appl. Phys.
Volume 57, Number 3, March 2012
|Number of page(s)||6|
|Section||Semiconductors and Devices|
|Published online||01 March 2012|
AlGaN/GaN MOS-HFETs based on InGaN/GaN MQW structures with Ta2O5 dielectric
National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan, P.R. China
2 Department of Electro-Optical Engineering, Kun Shan University, Yung-Kang Dist., Tainan City 71003, Taiwan, P.R. China
3 Institute of Microelectronics and Department of Electrical Engineering, Center for Micro/Nano Science and Technology, Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan City 70101, Taiwan, P.R. China
4 Department of Electrical Engineering, Fu Jen Catholic University, Zhong-Zheng Rd. 510, 24205 New Taipei City, Taiwan, P.R. China
a e-mail: firstname.lastname@example.org
Revised: 19 January 2012
Accepted: 8 February 2012
Published online: 1 March 2012
We report on metal-oxide-semiconductor (MOS) AlGaN/GaN heterostructure field effect transistors (HFETs) based on InGaN/GaN multiple quantum well (MQW) structure using Ta2O5 dielectric deposited by electron beam evaporation (EBE) simultaneously for surface passivation and as a gate insulator. The device features a 5-pair MQW layer inserted into the AlGaN/GaN two-channel HFET structure. It results in a raised potential barrier, which leads to better carrier confinement and effective access to the InGaN layer. However, it revealed a pronounced leakage current which may be generated from the bottom Si-doped GaN and/or the sidewall leakage paths due to the exposure of channels after mesa etching. Both passivated MQW-HFET and MOS MQW-HFET present enhanced dc- and pulsed-mode performance compared to unpassivated one. In terms of transfer characteristics, MOS MQW-HFET exhibits the larger and broader main peak yet smaller satellite peak relative to passivated MQW-HFET. The reduced gate and mesa-to-mesa leakage current indicates the successful passivation effect from EBE-Ta2O5 dielectric.
© EDP Sciences, 2012
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