Title :
Very high-power-density CW operation of GaAs/AlGaAs microwave heterojunction bipolar transistors
Author :
Bayraktaroglu, Burhan ; Barrette, J. ; Kehias, L. ; Huang, Chern I. ; Fitch, R. ; Neidhard, R. ; Scherer, R.
Author_Institution :
Coll. of Eng., North Carolina State Univ., Raleigh, NC, USA
Abstract :
Thermal instability of multi-emitter high-power microwave heterojunction bipolar transistors (HBTs) was eliminated using a novel heat spreading technique that regulates internal device currents to avoid the formation of hot spots. Devices with 2- and 3- mu m minimum emitter sizes and no intentional ballast resistors showed unconditionally stable CW operation up to the device electronic limitations. A record 10-mW/ mu m/sup 2/ power density was obtained at 10 GHz with 7-dB gain and 60% power-added efficiency. The highest efficiency was 67.2% at 9.3-mW/ mu m/sup 2/ power density. It was shown that stable high-power-density operation can be maintained at multiwatt output power levels.<>
Keywords :
III-V semiconductors; aluminium compounds; gallium arsenide; heterojunction bipolar transistors; power transistors; solid-state microwave devices; 10 GHz; 2 micron; 3 micron; 60 to 67.2 percent; 7 dB; CW operation; GaAs-AlGaAs; SHF; heat spreading technique; heterojunction bipolar transistors; high-power-density operation; microwave HBT; multiemitter device; multiwatt output power levels; stable CW operation; thermal instability; Electromagnetic heating; Electronic ballasts; Fabrication; Gallium arsenide; Heterojunction bipolar transistors; Microwave devices; Microwave theory and techniques; Power generation; Resistors; Temperature dependence;
Journal_Title :
Electron Device Letters, IEEE
