GaN-HEMTs devices with Single- and Double-heterostructure for power switching applications
IEEE Int. Reliab. Phys. Symp. (IRPS), Monterey, CA, USA, Apr. 14-18, pp. 3C1.1 - 3C1.7 (2013).
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We report on an extensive study of single- (SH) and double-heterostructure (DH) HEMTs based on gallium nitride, for power switching applications. The analysis is based on dc, pulsed and breakdown measurements, which were carried out on five different epitaxial structures.
We demonstrate that SH devices have a higher drain current than the DH ones. On the other hand, DH devices have much lower leakage current and higher breakdown voltage, thanks to the better confinement provided by the AlGaN layer placed on the back.
A measurable kink was also observed in these devices: this effect is more prominent in DH samples. A number of devices was also submitted to off-state step stress: once again, devices with a double heterostructure showed a good reliability. On the other hand, SH devices were found to have a poor stability, possibly due to the existence of punch-through leakage current components. Electroluminescence was also used as a tool for the characterization of the degradation process.
1 University of Padova, Dept of Information Engineering, Padova, Italy
2 Italian Universities Nano-Electronics Team (IUNET), 40125 Bologna, Italy
3 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, 12489 Berlin, Germany
Gallium Nitride, power HEMTs, reliability.