Research

Researchers Reveal High Performance AlGaN/GaN MIS-HEMTs

Author:ZHANG Zhili Update time:Mar 11, 2016

Gallium nitride (GaN)-based high electron mobility transistor (HEMT) power devices have demonstrated great application potential due to high current density, high switching speed, and low ON-resistance in comparison to the established silicon (Si)-based semiconductor devices. These superior characteristics make GaN HEMTs emerge as promising candidates for next-generation power converters.

Recently, Prof. ZHANG Baoshun's group, at Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences,reveals high performance AlGaN/GaN MIS-HEMTs. The gate dielectric layer and surface passivation layer are formed by the low pressure chemical vapor deposition (LPCVD) Si3N4. The LPCVD-Si3N4 MIS-HEMTs exhibit a high breakdown voltage 1162 V at IDS = 1 μA/mm, a low OFF-state leakage of 7.7 × 10-12 A/mm and an excellent ON/OFF current ratio ~ 1011. Compared with the static ON-resistance of 2.88 m?·cm2, the dynamic ON-resistance after high OFF-state drain bias stress at 600 V only increases to 4.89 m?·cm2. The power device figure of merit (FOM = BV2/RON.sp) is calculated as 469 MW·cm-2. The LPCVD-Si3N4/GaN interface state density is in the range of (1.4-5.3) × 1013 eV-1 cm-2 extracted by conventional conductance method. Finally, the gate insulator degradation of GaN-based MIS-HEMTs is analyzed by time-dependent-dielectric breakdown (TDDB) test. The lifetime is extrapolated to 0.01% of failure after 10 years at 300 K by fitting the data with a power law to gate voltage of 10.1 V. These results prove a great potential of LPVCD-Si3N4/AlGaN/GaN/Si MIS-HEMTs for high power switching applications.This work has been published in the journal Electron Devices, IEEE Transactions on, 2015, 63(2): 731 - 738.

This work was partly supported by the Key Technologies Support Program of  Jiangsu  Province  (grant  No. BE2013002-2). And the authors are grateful for the technical support provided by Nanofabrication Facility and Platform for Characterization and Test of SINANO, Chinese Academy of Science.

 

  

Fig. 1.  Schematic of an AlGaN/GaN MIS-HEMT with 20 nm Si3N4 as a gate dielectric and passivation layer.(Image by ZHANG Baoshun's group)

Fig. 2.  (a) Transfer curves of the devices at VDS of 10 V in semi-log scale. (b) Specific ON-resistance versus breakdown voltage     (c) Normalized dynamic RON with various OFF-state VDS stress and (d) Extrapolation of the tBD at 300 K towards low bias conditions.(Image by ZHANG Baoshun's group)

Contact information:Prof.ZHANG Baoshun

Suzhou Institute of Nano Tech and Nano Bionics ,Chinese Academy of Science 

Suzhou,Jiangsu 215123,China. 

E-mail:bszhang2006@sinano.ac.cn 


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