NOVEL SILICON-ON-INSULATOR STRUCTURESOFR ENERGY SELECTIVE VACUUM ULTRAVIOLET AND SOFT X-RAY DETECTORS

THE FABRICATION OF LOW DEFECT, ULTRATHIN SILICON-ON-INSULATOR (SOI) SUBSTRATES USING THE SEPARATION BY IMPLANTATION OF OXYGEN (SIMOX) PROCESS HAS RECENTLY BEEN DEMONSTRATED. THIS MATERIAL IS AN EXCELLENT CANDIDATE FOR FABRICATING VACUUM ULTRAVIOLET (VUV) AND SOFT X-RAY DETECTORS THAT (1) ARE INSENSITIVE TO UNDESIRABLE WAVELENGTHS (INCLUDING HARD X-RAY) AND (2) HAVE MINIMAL RESPONSE TO HIGH ENERGY PARTICLES SUCH AS ELECTRONS AND PROTONS. ONE ADVANTAGE OF FABRICATING DETECTORS ON SOI SUBSTRATES IS THAT THIS METHOD OFFERS THE ABILITY TO CHOOSE THE THICKNESS OF THE SILICON TOP LAYER, THEREBY CREATING DETECTORS SELECTIVELY SENSITIVE TO SPECIFIED ENERGY RANGES. DETECTORS SENSITIVE TO A CHOSEN ENERGY RANGE DO NOT REQUIRE A SPECTROMETER. A HIGH INTENSITY BEAM INCIDENT ON THE DETECTOR IS THEN POSSIBLE, AND, WITH THIS HIGH INTENSITY, HIGH RESOLUTION DETECTORS MAY BE PRODUCED. ADDITIONAL ADVANTAGES OF SOI OVER CONVENTIONAL DETECTORS INCLUDE GREATER STABILITY AND THE POTENTIAL TO INTEGRATE DETECTORS AND ASSOCIATED ELECTRONICS ONTO THE SAME RADIATION-HARD SUBSTRATE. IN ADDITION, THESE DETECTORS PROVIDE THE OPPORTUNITY TO FABRICATE MULTIDETECTOR ARRAYS FOR TWO-DIMENSIONAL IMAGING OF PLASMAS IN THE VUV AND SOFT X-RAYREGIONS. THIS APPLICATION, COMBINED WITH SILICON ADVANCED TECHNOLOGY AND THE INHERENT RADIATION HARDNESS OF SOI MATERIAL, PROVIDES THE POSSIBILITY TO STUDY THE TRANSIENT PHENOMENA AND TIME DEPENDENCE OF PLASMAS. IN PHASE I, THE FABRICATION OF VERY HIGH QUALITY SOI DETECTORS SELECTIVELY SENSITIVE TO VUV AND SOFT X-RAY RADIATION IS BEING UNDERTAKEN. INDIVIDUAL DEVICES RESPOND TO SPECIFIED BANDS IN THE VUV TO SOFT X-RAY WAVELENGTH REGION, AND AN ARRAY OF THESE DETECTORS CAN BE USED SIMULTANEOUSLY TO ANALYZE THE ENTIRE SPECTRUM. IN PHASE II, A DETECTOR ARRAY MAY BE FABRICATED FOR TWO-DIMENSIONAL PLASMA IMAGING.