J. RICHARD SHEALY Professor, School of Electrical and Computer Engineering 311 Phillips Hall Phone: (607) 255-4657 E-mail: shealy@ece.cornell.edu

After earning his doctorate, Shealy held a dual appointment at Cornell as a research associate and at General Electric as a principal staff scientist. ln 1983 he co-founded, and has chaired, the biennial international workshop on OMVPE (organometallic vapor phase epitaxy), a technique used for growing semiconductor crystals. He joined the faculty in 1987 and is active in developing Cornell's laboratory research in compound semiconductor materials and related graduate courses. At Cornell he is associated with thc National Nanofabrication Facility, Joint Services Electronics Program, and the DARPA Optoelectronics Technology Center.

We are researching experimental techniques for the fabrication of complex crystalline structures with unique semiconducting properties. One such technique, organometallic vapor-phase epitaxy (OMVPE), is currently used to produce compound-semiconductor structures with dimensional control on the atomic scale. Spatial confinement of electrons in such structures can result in new properties that will improve the performance of transistors and diode lasers. My research focuses on the use of OMVPE for the experimental production of new materials for high-efficiency lasers in both the infrared and the visible regions, and for ultra high-speed transistors. As the technology progresses, these techniques will be used to produce integrated optoelectronic circuits for applications including communications and remote sensing.

Research Interests and Activities:

Compound Semiconductor Materials for Ultra-High-Speed Transistors (Joint Services Electronics Program)

Advanced Crystal-Growth Techniques for New Semiconductors Using OMVPE (Strategic Defense Initiative Organization-lnnovative Science and Technology)

Selective Deposiion of Optoelectronic Materials with OMVPE (DARPA Optoelectronic Materials Center)

Selected Publications

• High-power broad-band AlGaN/GaN HEMT MMICs on SiC substrates Green, B.M.; Tilak, V.; Lee, S.; Kim, H.; Smart, J.A.;    Webb, K.J.; Shealy, J.R.;Eastman, L.F., Microwave Theory and Techniques, IEEE Transactions on , Volume: 49 Issue: 12 ,
Dec. 2001, Page(s): 2486 -2493

• Low-phase noise AlGaN/GaN FET-based voltage controlled oscillators (VCOs) Shealy, J.B.; Smart, J.A.; Shealy, J.R., Microwave and Wireless Components Letters, IEEE , Volume: 11 Issue: 6 , June 2001, Page(s): 244 -245

• Undoped AlGaN/GaN HEMTs for microwave power amplification  Eastman,      L.F.; Tilak, V.; Smart, J.; Green, B.M.; Chumbes, E.M.; Dimitrov, R.; Hyungtak Kim; Ambacher, O.S.; Weimann, N.; Prunty, T.; Murphy, M.; Schaff, W.J.; Shealy, J.R., Electron Devices, IEEE Transactions on , Volume: 48 Issue: 3, March 2001, Page(s): 479 -485

• Microwave performance of AlGaN/GaN metal insulator semiconductor field effect transistors on sapphire substrates Chumbes, E.M.; Smart, J.A.; Prunty, T.; Shealy, J.R. ,  Electron Devices, IEEE Transactions on , Volume: 48 Issue: 3 , March 2001, Page(s): 416-419

• High-power broad-band AlGaN/GaN HEMT MMICs on SiC substrates Green, B.M.; Tilak, V.; Lee, S.; Kim, H.; Smart, J.A.; Webb, K.J.; Shealy, J.R.;Eastman, L.F. , Microwave Theory and Techniques, IEEE Transactions on , Volume: 49 Issue: 12 , Dec. 2001,  Page(s): 2486 -2493

• Low-phase noise AlGaN/GaN FET-based voltage controlled oscillators (VCOs) Shealy, J.B.; Smart, J.A.; Shealy, J.R. Microwave and Wireless Components Letters, IEEE , Volume: 11 Issue: 6 , June 2001, Page(s): 244 -245

• Undoped AlGaN/GaN HEMTs for microwave power amplification, Eastman, L.F.; Tilak, V.; Smart, J.; Green, B.M.; Chumbes, E.M.; Dimitrov, R.; Hyungtak Kim; Ambacher, O.S.; Weimann, N.; Prunty, T.; Murphy, M.; Schaff, W.J.; Shealy, J.R.,  Electron Devices, IEEE Transactions on , Volume: 48 Issue: 3 , March 2001, Page(s): 479-485

• Microwave performance of AlGaN/GaN metal insulator semiconductor field Influence of barrier thickness on the high-power performance of AlGaN/GaN HEMTs,  Tilak, V.; Green, B.; Kaper, V.; Kim, H.; Prunty, T.; Smart, J.; Shealy, J.; Eastman, L.,  IEEE Electron Device Letters , Volume: 22 Issue: 11 , Nov. 2001, Page(s): 504 -506

• AlGaN/GaN high electron mobility transistors on Si(111) substrates, Chumbes, E.M.; Schremer, A.T.; Smart, J.A.; Wang, Y.; MacDonald, N.C.; Hogue, D.; Komiak, J.J.; Lichwalla, S.J.; Leoni, R.E., III.; Shealy, J.R., Electron Devices, IEEE Transactions on , Volume: 48 Issue: 3 , March 2001 Page(s): 420-426

• A broadband GaN push-pull distributed microwave power amplifier. Jong-Wook Lee; Green, B.M.; Tilak, V.; Sungjae Lee; Shealy, J.R.; Eastman, L.F.; Webb, K.J., Semiconductor Device Research Symposium, 2001 International , 2001, Page(s): 391 -393

• Progress in Si-based AlGaN HEMTs for RF power amplifiers Shealy, J.R, Silicon Monolithic Integrated Circuits in RF Systems, 2001. Digest of Papers. 2001, Topical Meeting on , 2001,  Page(s): 166 -169

• High-power AlGaN/GaN FET-based VCO sources, Shealy, J.B.; Smart, J.A.; Shealy, J.R., Microwave Symposium Digest, 2001 IEEE MTT-S International , Volume: 3 , May 2001, Page(s): 1427 -1430

• High-power broadband AlGaN/GaN HEMT MMICs on SiC substrates, B. Green, B.M.; Tilak, V.; Sungjae Lee; Hyungtak Kim; Smart, J.A.; Webb, K.J.; Shealy,  J.R.; Eastman, L.F. Microwave Symposium Digest, 2001 IEEE MTT-S International , Volume: 2 , 2001, Page(s): 1059 -1062

• Degradation characteristics of AlGaN-GaN high electron mobility transistors Hyungtak Kim; Tilak, V.; Green, B.M.; Ho-young Cha; Smart, J.A.; Shealy, J.R.; Eastman, L.F. Reliability Physics Symposium, 2001. Proceedings. 39th Annual. 2001 IEEE International, 2001, Page(s): 214 -218

• The effect of surface passivation on the microwave characteristics of undoped AlGaN/GaN HEMTs, Green, B.M.; Chu, K.K.; Chumbes, E.M.; Smart, J.A.; Shealy, J.R.; Eastman, L.F., IEEE Electron Device Letters , Volume: 21 Issue: 6 , June 2000, Page(s): 268 -270

• Cascode connected AlGaN/GaN HEMTs on SiC substrates, Green, B.M.; Chu, K.K.; Smart, J.A.; Tilak, V.; Hyungtak Kim; Shealy, J.R.; Eastman, L.F., IEEE Microwave and Guided Wave Letters [see also IEEE Microwave and Wireless Components Letters] , Volume: 10 Issue: 8 , Aug. 2000, Page(s): 316 -318

• Fixing the Curtice FET Model, Eastman, L.F.; Tilak, V.; Smart, J.; Green, B.M.; Chumbes, E.M.; Hyungtak Kim; Weimann, N.; Prunty, T.; Schaff, W.J.; Shealy, J.R., Microwave Journal, 3/2002, Pg 50

• Enhancement/Depletion Mode InGaP/AlGaAs PHEMT for High Efficiency Power Amplifiers, Eastman, L.F; Shealy, J.R.,   Microwave Journal, 5/2001, Pg 97

• Gallium Nitride-based Microwave and RF Control Devices, Shealy, J.R., Microwave Journal, 2/2001, Pg 100

. Improved RF Modeling Techniques for Enhanced AlGaN/GaN HFETs, S. Nuttinck, E. Gebara, J. Laskar, J. Shealy and M. Harris

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