The Characteristics of 6-inch GaN on Si RF HEMT with High Isolation Composited Buffer Layer Design

Hsien-Chin Chiu, Chang Gung University
Chong Rong Huang, Chang Gung University
Chia-Hao Liu, Chang Gung University
Chao-wei Chiu, Chang Gung University
Hsiang-Chun Wang, Chang Gung University

In this study, a 50-nm Al0.05Ga0.95N back barrier (BB) layer was used in an AlGaN/GaN high-electron-mobility transistor between the two-dimensional electron gas channel and Fe-doped/C-doped buffer layers. This BB layer can reduce the channel layer. The BB layer is affected by doped carriers in the buffer layer and the conduction energy band between the channel and the buffer layers. The Ion/Ioff ratio of the BB device was 3.43 × 105 and the ratio for the device without BB was 1.91 × 103. Lower leakage currents were obtained in the BB device because of the higher conduction energy band. The 0.25-μm gate length device with the BB exhibited a high current gain cutoff frequency of 26.9 GHz and power gain cutoff frequency of 54.7 GHz.

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