TEMPERATURE STABLE ALTERNATIVE TO LI COMPENSATION OF SILICON RADIATION SENSORS

SILICON X-RAY ENERGY SPECTROMETERS ARE A VERY IMPORTANT TOOL FOR ELEMENTAL ANALYSIS IN RESEARCH AND INDUSTRY. THE DEEP SENSITIVE DEPTHS REQUIRED FOR SI X-RAY DETECTORS AND SOME OTHER SI DETECTOR APPLICATIONS ARE USUALLY OBTAINED BY A LI COMPENSATION TECHNIQUE COMMONLY REFERRED TO AS LI DRIFTING. UNFORTUNATELY, THE ELI COMPENSATION, SI(LI), IS ONLY QUASISTABLE AT ROOM TEMPERATURE AND VERY UNSTABLE AT HIGHER TEMPERATURES. THIS TEMPERATURE STABILITY PROBLEM LIMITS THE PERFORMANCE AND GENERAL USEFULNESS OF THESE DETECTORS BY PROHIBITING MODERN DEVICE PROCESSING TECHNOLOGIES LIKE OXIDE SURFACE PASSIVATION AND HIGH TEMPERATURE CONTACT FORMATION. THE LACK OF OXIDE SURFACE PASSIVATION TO LIMIT NOISE FROM SURFACE LEAKAGE CURRENTS PLACES SEVERE RESTRICTIONS N THE MAXIMUM OPERATING TEMPERATURE OF LI-COMPENSATED DETECTORS. THE LACK OF A RUGGED OXIDE PASSIVATION AND RUGGED DIFFUSED OR IMPLANTED CONTACTS RESTRICTS THE OPERATING AMBIENT OF SI(LI) DEVICES. THIS PROJECT OUTLINES AN ALTERNATIVE APPROACH TO COMPENSATION OF SI WHICH SHOULD ALLOW SENSITIVE DEPTHS >3 MM, BE COMPATIBLE WITH HIGH TEMPERATURE OXIDE PASSIVATIONS, ALLOW HIGH TEMPERATURE CONTACT FORMATION, AND BE MUCH CHEAPER THAN LI DRIFTING. THIS NEW TECHNOLOGY RESULTS IN CHEAPER X-RAY DETECTORS WHICH OPERATE WELL AT TEMPERATURES OBTAINABLE WITH THERMOELECTRIC OR OTHER SIMPLE COOLING TECHNIQUES RATHER THAN LIQUID NITROGEN. IT ALSO MAKES IT POSSIBLE TO BUILD VERY LARGE AREA, DEEP SENSITIVE DEPTH DETECTORS AT REASONABLE PRICES.