Details

Autor(en) / Beteiligte

• Jie Liu
• Yugang Zhou
• Jia Zhu
• Yong Cai
• Lau, K.M.
• Chen, K.J.

Titel

DC and RF Characteristics of AlGaN/GaN/InGaN/GaN Double-Heterojunction HEMTs

Ist Teil von

• IEEE transactions on electron devices, 2007-01, Vol.54 (1), p.2-10

Ort / Verlag

New York, NY: IEEE

Erscheinungsjahr

2007

Quelle

IEEE Electronic Library (IEL)

Beschreibungen/Notizen

• We present the detailed dc and radio-frequency characteristics of an Al 0.3 Ga 0.7 N/GaN/In 0.1 Ga 0.9 N/GaN double-heterojunction HEMT (DH-HEMT) structure. This structure incorporates a thin (3 nm) In 0.1 Ga 0.9 N notch layer inserted at a location that is 6-nm away from the AlGaN/GaN heterointerface. The In 0.1 Ga 0.9 N layer provides a unique piezoelectric polarization field which results in a higher potential barrier at the backside of the two-dimensional electron gas channel, effectively improving the carrier confinement and then reducing the buffer leakage. Both depletion-mode (D-mode) and enhancement-mode (E-mode) devices were fabricated on this new structure. Compared with the baseline AlGaN/GaN HEMTs, the DH-HEMT shows lower drain leakage current. The gate leakage current is also found to be reduced, owing to an improved surface morphology in InGaN-incorporated epitaxial structures. DC and small- and large-signal microwave characteristics, together with the linearity performances, have been investigated. The channel transit delay time analysis also revealed that there was a minor channel in the InGaN layer in which the electrons exhibited a mobility slightly lower than the GaN channel. The E-mode DH-HEMTs were also fabricated using our recently developed CF 4 -based plasma treatment technique. The large-signal operation of the E-mode GaN-based HEMTs was reported for the first time. At 2 GHz, a 1times100 mum E-mode device demonstrated a maximum output power of 3.12 W/mm and a power-added efficiency of 49% with single-polarity biases (a gate bias of +0.5 V and a drain bias of 35 V). An output third-order interception point of 34.7 dBm was obtained in the E-mode HEMTs