Browsing by Author "Chang, C. -T."

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Normally-off operation AlGaN/GaN MOS-HEMT with high threshold voltage
(2010-09-02)
Chang, C. -T.
;
Hsu, T. -H.
;
Chang, E. Y.
;
Chen, Y. -C.
;
Trinh, H. -D.
Normally-off operation AlGaN/GaN high electron mobility transistors have been developed utilising a fluorine-based treatment technique combined with a metal-oxide-semiconductor gate architecture. Threshold voltage as high as 5.1 V was achieved by using an 16 nm-thick Al(2)O(3) gate oxide film. Additionally, the device performed a drain current density of 500 mA/mm and a peak transconductance of 100 mS/mm, which are comparable to the conventional normally-on devices.
Stable AlGaN/GaN high electron mobility transistors with tungsten nitride gate metallisation
(2009-12-03)
Lu, C. -Y.
;
Chang, E. Y.
;
Huang, J. -C.
;
Chang, C. -T.
;
Lee, C. -T.
An AlGaN/GaN high electron mobility transistor (HEMT) with tungsten nitride (WNx) Schottky gate fabricated on a sapphire substrate is presented. Gate forward current stress was chosen to evaluate the stability of the Schottky gate. After stress, this WNx HEMT remains stable, while the conventional Ni/Au HEMT shows performance degradation and failure. The maximum output power density from this device is 5 W/mm at 2 GHz. A combination of these findings indicates the robust performance of this WNx material and its potential as a Schottky gate for AlGaN/GaN HEMTs.