Applied Physics Letters · 2004 · 99 citations · 10 references
EngineeringElectrical EngineeringMaterials ScienceMicroelectronicsMicrowave EngineeringSemiconductor DevicesDevice CharacterizationDopingField-effect TransistorsHigh-frequency Semiconductor DevicesWide Band Gap SemiconductorsWide-bandgap SemiconductorsChannel DopingChannel Doping EffectsCompositional GradingCurrent DensityCutoff FrequencyHigh-electron-mobility TransistorsMicrowave DevicesTransconductance
We discuss an AlGaN/GaN metal–semiconductor field-effect transistor (MESFET) structure grown without any impurity doping in the channel. A high-mobility polarization-induced bulk channel charge was created by grading the channel region linearly from GaN to Al0.3Ga0.7N over 1000 Å. This polarization-doped FET (PolFET) was fabricated and tested under dc and rf conditions. Current density of 850 mA/mm and transconductance of 93 mS/mm was observed under dc conditions. The 0.7 μm gate length devices had a cutoff frequency, fτ=19 GHz, and maximum oscillation frequency, fmax=46 GHz. We demonstrate that the PolFETs perform better than comparable MESFETs with impurity-doped channels, and are suitable for high power microwave applications. An important advantage of these devices over AlGaN/GaN high electron mobility transistors is that the transconductance versus gate voltage profile can be tailored by compositional grading for better large-signal linearity.
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The toughest transistor yet [GaN transistors]
L.F. Eastman, Umesh K. Mishra · IEEE Spectrum · 2002 · 231 citations
Microwave performance of GaN MESFETs
S.C. Binari, L.B. Rowland, W. Kruppa et al. · Electronics Letters · 1994 · 153 citations