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ABSTRACT: An In<sub>0.53</sub>Ga<sub>0.47</sub>As/InAs<sub>0.3</sub>P<sub>0.7</sub> composite channel high electron mobility transistor (HEMT) structure was grown by molecular beam epitaxy. Room-temperature Hall measurement showed that the device wafer had an electron mobility of 7300 cm<sup>2</sup>/V s and a sheet electron density of 3×10<sup>12</sup> cm<sup>-2</sup>. The fabricated HEMT devices with a gate length of 0.25 μm exhibited excellent DC and microwave performance with a peak extrinsic transconductance of 888.3 mS/mm, a cutoff frequency (f<sub>T</sub>) of 115 GHz, and a maximum frequency of oscillation of 137 GHz. This is believed to be the first report of InGaAs/InAsP composite channel HEMTs. The f<sub>T</sub> is the highest ever reported for any composite channel HEMTs with the same gate length.
Electronics Letters 04/2006; · 0.96 Impact Factor
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ABSTRACT: In this paper we report growth, fabrication and characterization of In<sub>0.52</sub>Al<sub>0.4</sub>sAs/In<sub>0.53</sub>Ga<sub>0.47</sub>As/InAs<sub>0.3</sub>P<sub>0.7</sub> composite channel HEMTs with a gate length of 0.25 μm. In comparison with InAlAs/InGaAs/InP composite channel HEMTs, these devices have better band structure for transferring electrons to the composite channel under high electric field, thus exhibit excellent DC and microwave performance with a peak extrinsic transconductance of 888.3 mS/mm, an f<sub>T</sub> of 115 GHz, and an f<sub>max</sub> of 137 GHz. To our knowledge, this is the first report of InAlAs/InGaAs/InAsP composite channel HEMTs. The f<sub>T</sub> is the highest ever reported for any composite channel HEMTs with the same gate length.
Microwave Conference Proceedings, 2005. APMC 2005. Asia-Pacific Conference Proceedings; 01/2006
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ABSTRACT: Self-aligned T-gate AlGaN/GaN high electron mobility transistors (HEMTs) were fabricated on a sapphire substrate using a thin Ti/Al/Ti/Au ohmic layer. To suppress the gate leakage current, the ohmic contact annealing was performed in a furnace. The self-aligned HEMTs with 0.25 μm gate length and 100 μm width exhibit good pinch-off characteristics, a transconductance of 146 mS/mm, an extrinsic unity current gain cutoff frequency of 38 GHz and a maximum oscillation frequency of 130 GHz.
Electronics Letters 10/2004; · 0.96 Impact Factor
