VIB-8 millimeter-wave Gunn oscillators with temperature-compensated impurity profiles
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IEEE TRANSACTIONS ON ELECTRON DEVICES, VOL. ED-33, NO. 11, NOVEMBER 1986 1867 tact resistance measurements made on six transmission line struc- tures on a single wafer show excellent uniformity of the nonalloyed contacts fabricated in this work. *Research supported through an industrial grant from Hewlett-Packard Microwave Technology Division, Santa Rosa, CA, and also by SRC under Contract 84-02-047. [1] C. Y. Chang, Y. K. Fang, and S. M. Sze, Solid-State Electron., vol. **M. I. T. Lincoln Lab., Lexington, MA 02173. 14, pp. 541-550,1971. VIB-8Millimeter-WaveGunnOscillatorswithTemperature- Compensated Impurity Profiles-R. L. Ross, A. C. Paolella, D. A.Dekanski,and J. Ondria,"USAElectronicsTechnologyand Devices Laboratory, SLCET-EA, Fort Monmouth, NJ 07703-5302, and Y. Anand and V. J. Higgins, MIA-COM, South Avenue Bur- lington, MA 01803. In order to improve the thermal efficiency and output power of millimeter-wave Gunn diode oscillators, device structures with tai- lored impurity doping profiles have been grown by computer-au- tomated molecular-beam epitaxy. Requirements for solid-state CW oscillators at microwave/mil- limeter-wave frequencies are currently contested between silicon IMPATT's and gallium arsenide and indium phosphide Gunn diodes. Each technology has its own merits, but none fulfills simul- taneously the three critical parameters of high efficiency, high power,andlowFMnoise.Moreimportant,fornext-generation millimeter-wave systems, it may not be any of the three parameters which results in a choice between these technologies but, rather, whether the technology lends itself to monolithic integration: the combining of millimeter-wave devices onto a single substrate. The choice is then limited to GaAs or InP. Of these two materials, only GaAs offers a near-term maturing monolithic technology. Current state-of-the-art GaAs Gunn oscillators have relatively poor efficiency: typically 5 percent at 35 GHz and 1.5 percent at 60 GHz. Historically, attempts to improve this low value have been mainly directed at improving the thermal efficiency of the device byvariousheatsinkingtechniques, i.e., platedheatsink,integral heatsink, diamond impregnation, and, most recently, by substrate removal. Little or no research has been directed at redesigning the electronic structure of the basic Gunn diode, in an attempt to im- prove its thermal dissipation properties. One such approach would be to control the doping profile of the active region to account for nonuniform thermal dissipation in that layer. For the first time, millimeter-wave GaAs G u m structures have been grown by computer-automated molecul.ar-beam epitaxy wherein the active region is graded in impurity concentration. I3y shaping the carrier concentration along the active n-layer, the del- eterious temperature effects produced by standard flat profile de- signs can, essentially, be eliminated. A number of structures with varying profiles have been processed, packaged and evaluated for Ku-band operation. When compared with similar structures grown with flat active-region profiles, a 30- to 40-percent increase in e:f- ficiency and output power was realized, indicating that temperature compensatedimpurityprofilesareeffectiveinimprovingdevice performance. *Battelle Institute, Research Triangle Park, NC 2'7709.
Transcript of VIB-8 millimeter-wave Gunn oscillators with temperature-compensated impurity profiles
IEEE TRANSACTIONS ON ELECTRON DEVICES, VOL. ED-33, NO. 11, NOVEMBER 1986 1867
tact resistance measurements made on six transmission line struc- tures on a single wafer show excellent uniformity of the nonalloyed contacts fabricated in this work.
*Research supported through an industrial grant from Hewlett-Packard Microwave Technology Division, Santa Rosa, CA, and also by SRC under Contract 84-02-047.
[1] C. Y . Chang, Y . K. Fang, and S. M . Sze, Solid-State Electron., vol. **M. I. T. Lincoln Lab., Lexington, MA 02173.
14, pp. 541-550, 1971.
VIB-8 Millimeter-Wave Gunn Oscillators with Temperature- Compensated Impurity Profiles-R. L. Ross, A. C. Paolella, D. A. Dekanski, and J. Ondria," USA Electronics Technology and Devices Laboratory, SLCET-EA, Fort Monmouth, NJ 07703-5302, and Y. Anand and V. J . Higgins, MIA-COM, South Avenue Bur- lington, MA 01803.
In order to improve the thermal efficiency and output power of millimeter-wave Gunn diode oscillators, device structures with tai- lored impurity doping profiles have been grown by computer-au- tomated molecular-beam epitaxy.
Requirements for solid-state CW oscillators at microwave/mil- limeter-wave frequencies are currently contested between silicon IMPATT's and gallium arsenide and indium phosphide Gunn diodes. Each technology has its own merits, but none fulfills simul- taneously the three critical parameters of high efficiency, high power, and low FM noise. More important, for next-generation millimeter-wave systems, it may not be any of the three parameters
which results in a choice between these technologies but, rather, whether the technology lends itself to monolithic integration: the combining of millimeter-wave devices onto a single substrate. The choice is then limited to GaAs or InP. Of these two materials, only GaAs offers a near-term maturing monolithic technology.
Current state-of-the-art GaAs Gunn oscillators have relatively poor efficiency: typically 5 percent at 35 GHz and 1.5 percent at 60 GHz. Historically, attempts to improve this low value have been mainly directed at improving the thermal efficiency of the device by various heatsinking techniques, i.e., plated heatsink, integral heatsink, diamond impregnation, and, most recently, by substrate removal. Little or no research has been directed at redesigning the electronic structure of the basic Gunn diode, in an attempt to im- prove its thermal dissipation properties. One such approach would be to control the doping profile of the active region to account for nonuniform thermal dissipation in that layer.
For the first time, millimeter-wave GaAs G u m structures have been grown by computer-automated molecul.ar-beam epitaxy wherein the active region is graded in impurity concentration. I3y shaping the carrier concentration along the active n-layer, the del- eterious temperature effects produced by standard flat profile de- signs can, essentially, be eliminated. A number of structures with varying profiles have been processed, packaged and evaluated for Ku-band operation. When compared with similar structures grown with flat active-region profiles, a 30- to 40-percent increase in e:f- ficiency and output power was realized, indicating that temperature compensated impurity profiles are effective in improving device performance.
*Battelle Institute, Research Triangle Park, NC 2'7709.
