Browsing by Author "Liu, Kuan-Shin"

Now showing 1 - 2 of 2

Influence of AlN buffer layer thickness on material and electrical properties of InAlN/GaN high-electron-mobility transistors
(2015-07-01)
Huang, Wei-Ching
;
Liu, Kuan-Shin
;
Wong, Yuen-Yee
;
Hsieh, Chi-Feng
;
Chang, Edward-Yi
The influence of the thickness of a high-temperature AlN (HT-AlN) buffer layer on the properties of an InAlN/GaN high-electron-mobility transistor (HEMT) grown on a sapphire substrate was investigated. As revealed by atomic force microscope analysis, a rougher surface and larger grain size were observed with a thicker buffer layer. The larger grains promoted the two-dimensional (2D) growth mode of the GaN layer at the initial growth stage. This suppressed oxygen incorporation at the GaN/HT-AlN interface and thus improved the resistivity of the GaN layer. Moreover, the lower grain density also resulted in enhanced GaN crystal quality of the GaN layer. As a consequence, the electrical properties of the InAlN/GaN HEMT device, such as output current, transconductance and off-state breakdown voltage, were improved by increasing the HT-AlN buffer layer thickness. (C) 2015 The Japan Society of Applied Physics
The effects of Growth Parameters on the Electrical Properties in InAlN/AlN/GaN High-Electron-Mobility Transistors (HEMTs)
(2014-01-01)
Huang, Wei-Ching
;
Wong, Yuen-Yee
;
Liu, Kuan-Shin
;
Hsieh, Chi-Feng
;
Chang, Edward Yi
The electrical properties in the InAlN/AlN/GaN high electron mobility transistor grown by metal-organic vapor deposition (MOCVD) with different growth parameters were investigated in this study. We observed that two-dimensional electron gas (2DEG) channel was influenced by thickness of AlN spacer layer and a stable stage prior to the growth of AlN spacer layer. The TEM images showed the generation of dislocations at interface between AlN/GaN and InAlN/AlN with the thicker AlN spacer layer. These dislocations acted as electron scattering center and degraded the electron mobility in the 2DEG channel. Besides, a too long stable stage also appeared degradation in the electron mobility due to the etching effect of H-2 gas. By optimizing growth parameters, the highest electron mobility of 890 cm(2)/V.s