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- Borg, Malin, 1978, et al.
(författare)
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Effect of gate length in InAs/AlSb HEMTs biased for low power or high gain
- 2008
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Ingår i: Solid-State Electronics. - : Elsevier BV. - 0038-1101. ; 52:5, s. 775-781
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Tidskriftsartikel (refereegranskat)abstract
- The effect of gate-length variation on DC and RF performance of InAs/AlSb HEMTs, biased for low DC power consumption or high gain, is reported. Simultaneously fabricated devices, with gate lengths between 225 nm and 335 nm, have been compared. DC measurements revealed higher output conductance gds and slightly increased impact ionization with reduced gate length. When reducing the gate length from 335 nm to 225 nm, the DC power consumption was reduced by approximately 80% at an fT of 120 GHz. Furthermore, a 225 nm gate-length HEMT biased for high gain exhibited an extrinsic fT of 165 GHz and an extrinsic fmax of 115 GHz, at a DC power consumption of 100 mW/mm. When biased for low DC power consumption of 20 mW/mm the same HEMT exhibited an extrinsic fT and fmax of 120 GHz and 110 GHz, respectively.
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- Lefebvre, Eric, 1975, et al.
(författare)
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Gate-recess Technology for InAs/AlSb HEMTs
- 2009
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Ingår i: IEEE Transactions on Electron Devices. - 1557-9646 .- 0018-9383. ; 56:9, s. 1904-1911
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Tidskriftsartikel (refereegranskat)abstract
- The gate-recess technology for Si δ-doped InAs/AlSbhigh-electron-mobility transistors (HEMTs) has been investigated by combining atomic force microscopy (AFM) inspection of the gate-recess versus time with electrical device characterization. Deposition of the gate metal on the In0.5Al0.5As protection layer or on the underlying AlSb Schottky layer resulted in devices suffering from high gate-leakage current. Superior dc and high frequency device performance were obtained for HEMTs with an insulating layer between the gate and the Schottky layer resulting in a reduction of the gate leakage current IG by more than two orders of magnitude at a drain-to-source voltage VDS of 0.1 V. The existence of this intermediate insulating layer was evident from the electrical measurements. AFM measurements suggested that the insulating layer was due to a native oxidation of theAlSb Schottky layer. The insulated-gate HEMT with a gate length of 225 nm exhibited a maximum drain current ID higher than 500 mA/mm with good pinchoff characteristics, a dc transconductance gm of 1300 mS/mm, and extrinsic values for cutoff frequency fT and maximum frequency of oscillation fmax of 160 and 120 GHz, respectively.
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| 9. |
- Malmkvist, Mikael, 1978, et al.
(författare)
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Electrical Characterization and Small-Signal Modeling of InAs/AlSb HEMTs for Low-Noise and High-Frequency Applications
- 2008
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Ingår i: IEEE Transactions on Microwave Theory and Techniques. - 0018-9480 .- 1557-9670. ; 56:12, s. 2685-2691
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Tidskriftsartikel (refereegranskat)abstract
- Electrical characterization and modeling of 2 times 50 um gatewidth InAs/AlSb HEMTs with 225 nm gate-length have been performed. The fabricated devices exhibited a transconductance gm of 650 mS/mm, an extrinsic cutoff frequency fT and an extrinsic maximum frequency of oscillation fmax of 120 and 90 GHz, respectively, already at a low VDS of 0.2 V. A minimum noise figure less than 1 dB between 2-18 GHz was achieved at a dc power consumption of only 10 mW/mm. This demonstrates the potential of InAs/AlSb HEMTs for low-power, low-noise applications. To account for the elevated gate-leakage current lG in the narrow-bandgap InAs/AlSb HEMT, the conventional field-effect transistor small-signal model has been extended. The relatively high IG was modeled by shunting both Cgs and Cgd with Rgs and Rgd, respectively. As a result, the small-signal S-parameters were more accurately modeled, especially for frequencies below 10 GHz. Utilizing this modeling approach, excellent agreement was obtained between measured and modeled S-parameters, unilateral power gain U (Mason's gain) and stability factor K.
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