HIGH QUALITY ULTRA-THIN CRYSTALLINE SILICON-ON-INSULATOR FOR SOFT X-RAY AND VACUUM ULTRAVIOLET DETECTORS

METHODS OF PRODUCING VERY LOW DEFECT, HIGH QUALITY, ULTRA THIN SILICON-ON-INSULATOR (SOI) WAFERS HAVE BEEN DEVELOPED USING THE SEPARATION BY IMPLANTATION OF OXYGEN (SIMOX) PROCESS. THE DENSITY OF THREADING DISLOCATION DEFECTS HAS BEEN REDUCED BY MORE THAN FIVE ORDERS OF MAGNITUDE COMPARED TO CONVENTIONAL SIMOX FABRICATION TECHNIQUES. THIS MATERIAL IS AN EXCELLENT CANDIDATE FOR ENERGY SELECTIVE SILICON RADIATION DETECTORS (PHOTOCONDUCTORS). THE SIMOX STRUCTURE CAN BE FABRICATED WITH A SILICON TOP LAYER OF ALMOST ANY THICKNESS DOWN TO ABOUT 500 ANGSTROMS SO THAT THEDETECTOR CAN BE MADE SELECTIVELY SENSITIVE TO RADIATION RANGING FROM VACUUM ULTRAVIOLET (VUV) TO SOFT X-RAY WAVELENGTHS. RECENT PROGRESS IN SIMOX RESEARCH PERMITS FABRICATION OF SUCH DEVICES. IN PHASE I, AN ULTRA THIN (500TO 1,000 ANGSTROMS) SIMOX STRUCTURE WILL BE DEVELOPED AND A SILICON SELECTIVE RADIATION DETECTOR WILL BE FABRICATED. THE DETECTOR WILL BE A SIMPLE PHOTOCONDUCTIVE DEVICE THAT WILL BE TESTED WITH SOFT X-RAY AND UV RADIATION IN THE PRESENCE OF PARTICLE RADIATION. PHASE II WILL PRODUCE AN ARRAY OF DETECTOR ELEMENTS AND EXAMINE FABRICATION OF DIODE-TYPE DETECTORS (PHOTODIODES). TESTS OF THE DETECTORS AS A DIAGNOSTIC FOR AN ENERGETIC PLASMA ALSO WILL BE CONDUCTED IN PHASE II.