ADVANCED GAAS FET FOR LOW NOISE MICROWAVE AND MILLIMETER-WAVE MMIC FREQUENCY SOURCES

FREQUENCY SOURCES (OSCILLATORS) ARE IMPORTANT COMPONENTS IN MICROWAVE AND MILLIMETER-WAVE SYSTEMS. GAAS MESFET TECHNOLOGY, IN SPITE OF ITS SUCCESS IN A VARIETY OF DISCRETE AND MONOLITHIC MICROWAVE INTEGRATED CIRCUITS (MMIC'S), IS NOT SATISFACTORY FOR OSCILLATOR APPLICATIONS DUE TO THE OBSERVED EXCESSIVE FM NOISE COMPARED TO SI BIPOLAR TRANSISTOR OR GUNN DIODE COMPONENTS. SI BIPOLAR TRANSISTORS AND GUNN DIODES ARE HOWEVER NOT SUITABLE FOR MONOLITHIC INTEGRATION OF MICROWAVE CIRCUITS ON GAAS. THE HIGHER FM NOISE OF GAAS MESFET OSCILLATORS HAS BEEN ATTRIBUTED TO THE HIGHER 1/F NOISE OF THE GAAS MESFET DEVICE. MICROWAVE MONOLITHICS INCORPORATED HAS DEVELOPED A "FLASH ANNEALING" TECHNIQUE WHICH MAY SUBSTANTIALLY REDUCE THE 1/F NOISE OF GAAS FET'S. GAAS MESFET'S WHICH HAVE BEEN FABRICATED BY THIS PROPRIETARY PROCESS, AND SHORT GATE GAAS JFET'S WHICH ARE VIABLE UTILIZING THE FLASH ANNEALING FABRICATION TECHNOLOGY, WILL BE MEASURED TO ASCERTAIN THEIR 1/F NOISE PERFORMANCE. THESE MEASURED RESULTS WILL BE COMPARED WITH PUBLISHED DATA FOR SI BIPOLAR TRANSISTORS AND GAAS MESFET'S. AN IMPROVED DEVICE WILL BE DESIGNED AFTER THE EXPECTED REDUCTION IN NOISE IS VERIFIED, AND DESIGN OF A LOW NOISE LOCAL OSCILLATOR WILL BE INITIATED IN PROGRAM PHASE I. EFFORTS OF PHASE II WILL BE CONCENTRATED ON THE OPTIMIZATION OF THE SELECTED LOW 1/F NOISE FET TECHNOLOGY AND THE FABRICATION OF A HIGH PERFORMANCE MONOLITHIC LOCAL OSCILLATOR DEMONSTRATION CIRCUIT.