High-performance 0.15-μm-gate-length pHEMTs enhanced with a low-temperature-grown GaAs buffer

Actis, R.; Nichols, K. B.; Kopp, W.; Rogers, T. J.; Smith, F. W.

doi:10.1109/mwsym.1995.405950

Cited by 7 publications

(2 citation statements)

References 4 publications

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“…The holes that are generated from impact ionization can create a leakage path inside the buffer; hence, these holes have a positive fixed charge which enhances the injection of hot electrons to the channel and buffer and increases the reverse gate leakage current [27,30]. The high resistivity of the LT buffer also helps to make the electrons from source to drain more confined in the channel layer [31] and reduces leakage to the buffer. Furthermore, the In 0.52 Al 0.48 As Barrier 1 layer, grown after the LT-In 0.52 Al 0.48 As buffer (refer Figure 2 on the XMBE56 epitaxial layer), does not use the super lattice (SL) structure, as previously performed by other researchers [28,32].…”

Section: Direct Current (Dc) Characteristicsmentioning

confidence: 99%

New Submicron Low Gate Leakage In0.52Al0.48As-In0.7Ga0.3As pHEMT for Low-Noise Applications

et al. 2021

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Conventional pseudomorphic high electron mobility transistor (pHEMTs) with lattice-matched InGaAs/InAlAs/InP structures exhibit high mobility and saturation velocity and are hence attractive for the fabrication of three-terminal low-noise and high-frequency devices, which operate at room temperature. The major drawbacks of conventional pHEMT devices are the very low breakdown voltage (<2 V) and the very high gate leakage current (∼1 mA/mm), which degrade device and performance especially in monolithic microwave integrated circuits low-noise amplifiers (MMIC LNAs). These drawbacks are caused by the impact ionization in the low band gap, i.e., the InxGa(1−x)As (x = 0.53 or 0.7) channel material plus the contribution of other parts of the epitaxial structure. The capability to achieve higher frequency operation is also hindered in conventional InGaAs/InAlAs/InP pHEMTs, due to the standard 1 μm flat gate length technology used. A key challenge in solving these issues is the optimization of the InGaAs/InAlAs epilayer structure through band gap engineering. A related challenge is the fabrication of submicron gate length devices using I-line optical lithography, which is more cost-effective, compared to the use of e-Beam lithography. The main goal for this research involves a radical departure from the conventional InGaAs/InAlAs/InP pHEMT structures by designing new and advanced epilayer structures, which significantly improves the performance of conventional low-noise pHEMT devices and at the same time preserves the radio frequency (RF) characteristics. The optimization of the submicron T-gate length process is performed by introducing a new technique to further scale down the bottom gate opening. The outstanding achievements of the new design approach are 90% less gate current leakage and 70% improvement in breakdown voltage, compared with the conventional design. Furthermore, the submicron T-gate length process also shows an increase of about 58% and 33% in fT and fmax, respectively, compared to the conventional 1 μm gate length process. Consequently, the remarkable performance of this new design structure, together with a submicron gate length facilitatesthe implementation of excellent low-noise applications.

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Section: Direct Current (Dc) Characteristicsmentioning

confidence: 99%

New Submicron Low Gate Leakage In0.52Al0.48As-In0.7Ga0.3As pHEMT for Low-Noise Applications

et al. 2021

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“…Table 1 is a summary of the highest-power unmatched GaN HEMT commercial off-the-shelf (COTS) devices available in 2014. An unmatched device is a transistor without input or output impedance matching networks, and, consequently, optimum terminations are reactive and low impedance, requiring external matching networks to SiC FET [61] GaAs PHEMT [55] GaAs PHEMT [52] GaAs HBT [59] GaAs HBT [57] x x…”

Section: Unmatched Gan Hemt Devicesmentioning

confidence: 99%