LOW COST AVALANCHE PHOTODIODES FOR SCINTILLATION DETECTION

SILICON AVALANCHE PHOTODIODES (APDS) HAVE BEEN SHOWN TO BE NEARLY AN IDEAL REPLACEMENT FOR PHOTOMULTIPLIER TUBES (PMTS) IN SCINTILLATION DETECTION APPLICATIONS. HOWEVER, BECAUSE OF THEIR GREAT EXPENSE (TYPICALLY APDS COST TEN TIMES AS MUCH AS AN EQUIVALENT PMT) APDS HAVE NOT BEEN WIDELY USED. THE HIGH COST OF APDS IS DUE TO THE LOW YIELD, LABOR-INTENSIVE MANUFACTURING PROCESS USED TO PRODUCE THEM. THE PURPOSE OF THIS PROJECT IS TO DEVELOP A NEW APD DESIGN THAT CAN BE MANUFACTURED ENTIRELY USING AUTOMATIC METHODS EMPLOYED IN THE INTEGRATED CIRCUIT (IC) INDUSTRY. THE GOAL OF THE PHASE I EFFORT IS TO DEMONSTRATE THAT IT IS POSSIBLE TO FABRICATE APDS WITH PERFORMANCE COMPARABLE TO PRESENT DEVICES USING STANDARD SILCION IC PROCESSING TECHNOLOGIES. DURING PHASE I AN APPROPRIATE APD STRUCTURE WILL BE DESIGNED AND THE NECESSARY FABRICATION STEPS DEVELOPED AND TESTED. BY THE END OF PHASE I, APDS WILL BE FABRICATED USING THIS PROCESS AND TESTED AS DETECTORS. PHASE II OF THIS EFFORT WILL CONTINUE THE RESEARCH AND EXAMINE WAYS TO IMPROVE PERFORMANCE AND REDUCE COST TO PRODUCE A PROCESS THAT IS COMPATIBLE WITH LARGER SCALE, LOW COST SILICON DEVICE MANUFACTURING. IF SUCCESSFUL, THE PROPOSED RESEARCH WOULD RESULT IN A LOW COST SOLID STATE ALTERNATIVE TO PMTS.