TY - JOUR
T1 - DC, RF, and microwave noise performance of AlGaN-GaN field effect transistors dependence of aluminum concentration
AU - Lu, Wu
AU - Kumar, Vipan
AU - Piner, Edwin L.
AU - Adesida, Ilesanmi
N1 - Funding Information:
Manuscript received July 8, 2002; revised February 24, 2003. This work was supported by the Air Force under Contract AF 98-46029 and the ONR under Contracts N00014-01-1-1000 and N00014-01-1-1072 monitored by Dr. J. Zolper. The review of this paper was arranged by Editor M. J. Deen. W. Lu is with the Department of Electrical Engineering, The Ohio State University, Columbus, OH 43210 USA (e-mail: lu@ee.eng.ohio-state.edu). V. Kumar and I. Adesida are with the Department of Electrical and Computer Engineering and Microelectronics Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA. E. L. Piner was with the ATMI/Epitronics, Phoenix, AZ 85027 USA. He is now with the Nitronex Inc., Raleigh, NC 27606 USA. Publisher Item Identifier 10.1109/TED.2003.812083.
PY - 2003/4
Y1 - 2003/4
N2 - AlGaN-GaN heterostructures with different Al concentrations (20, 27, and 35%) were grown by metal-organic vapor phase epitaxy (MOVPE) on sapphire substrates. Ti-Al-Ti-Au ohmic contact optimization was investigated at different temperatures and annealing time. Heterojunction field effect transistors (HFET) with a gate length of 0.25 μm were fabricated. Low contact resistances of 0.2, 0.26, and 0.33 Ω · mm were obtained for HFET device samples with Al concentrations of 20, 27, and 35%, respectively. For Al concentration of 20, 27, and 35%, the AlGaN-GaN devices exhibited extrinsic transconductances of 143, 152, and 210 mS/mm, Idss of 398, 566, and 784 mA/mm, unity cutoff frequencies (fT) of 24.9, 34.6, and 50 GHz and maximum oscillation frequencies (fMAX) of 54.9, 61.8, and 100.9 GHz and minimum noise figures (Fmin) of 2.01, 1.47, and 1.02 dB at 12 GHz, respectively. The calculated minimum noise figures have a good agreement with the measured values for all the devices with different Al mole fractions. The noise analysis shows that intrinsic noise of these AlGaN-GaN FETs plays a prominent part in the noise behavior because of Improved device parasitics.
AB - AlGaN-GaN heterostructures with different Al concentrations (20, 27, and 35%) were grown by metal-organic vapor phase epitaxy (MOVPE) on sapphire substrates. Ti-Al-Ti-Au ohmic contact optimization was investigated at different temperatures and annealing time. Heterojunction field effect transistors (HFET) with a gate length of 0.25 μm were fabricated. Low contact resistances of 0.2, 0.26, and 0.33 Ω · mm were obtained for HFET device samples with Al concentrations of 20, 27, and 35%, respectively. For Al concentration of 20, 27, and 35%, the AlGaN-GaN devices exhibited extrinsic transconductances of 143, 152, and 210 mS/mm, Idss of 398, 566, and 784 mA/mm, unity cutoff frequencies (fT) of 24.9, 34.6, and 50 GHz and maximum oscillation frequencies (fMAX) of 54.9, 61.8, and 100.9 GHz and minimum noise figures (Fmin) of 2.01, 1.47, and 1.02 dB at 12 GHz, respectively. The calculated minimum noise figures have a good agreement with the measured values for all the devices with different Al mole fractions. The noise analysis shows that intrinsic noise of these AlGaN-GaN FETs plays a prominent part in the noise behavior because of Improved device parasitics.
KW - AlGaN
KW - GaN
KW - HEMTs
KW - Microwave noise
KW - Minimum noise figure
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U2 - 10.1109/TED.2003.812083
DO - 10.1109/TED.2003.812083
M3 - Article
AN - SCOPUS:0037480770
VL - 50
SP - 1069
EP - 1074
JO - IEEE Transactions on Electron Devices
JF - IEEE Transactions on Electron Devices
SN - 0018-9383
IS - 4
ER -