LOW COST, LARGE AREA EPITAXIAL SILICON DETECTORS FOR SAMPLING CALORIMETERS

A LOW-COST APPROACH TO FABRICATING LARGE AREA SILICON DIODES FOR SAMPLING CALORIMETERS IS PROPOSED. SUCH SAMPLINGCALORIMETERS ARE NEEDED IN HIGH ENERGY PARTICLE DETECTORS SUCH AS THOSE USED IN THE SUPERCOLLIDER. THE APPROACH IS BASED ON THE USE OF HIGH RESISTIVITY SILICON GROWN BY EPITAXIAL GROWTH TECHNIQUES, AS OPPOSED TO THE CONVENTIONAL APPROACH OF USING EXPENSIVE, FLOAT-ZONE GROWN, HIGH RESISTIVITY SILICON WHICH MUST SUBSEQUENTLY BE DIFFUSED AND CONTACTED FOR DEVICE FABRICATION. THE QUALITY OF HIGH RESISTIVITY SILICON HAS NOW BEEN DEVELOPED TO THE POINT WHERE THIS APPROACH IS FEASIBLE. ONCE THE EPITAXIAL GROWTH OF LARGE AREA, HIGH RESISTIVITY MATERIAL HAS BEEN DEMONSTRATED, WE PLAN TO GROW THE ENTIRE PIN SILICON DIODE STRUCTURE IN ONE REACTOR, IN ONE OPERATION. THIS WILL ELIMINATE THE NEED FOR SUBSEQUENT DIFFUSION OR ION IMPLANTATION, AND THEREBY SIGNIFICANTLY REDUCE COST. THE PROGRAM CONSISTS OF FOUR TASKS: INVESTIGATION INTO THE GROWTH OF HIGH RESISTIVITY MATERIAL OF 150 TO 200 MICROMETERTHICKNESS, GROWTH OF THE THICK LAYERS, GROWTH OF THE COMPLETE PIN STRUCTURE, AND ANALYSIS OF THE EPITAXIAL LAYER STRUCTURES. COMPLETED DEVICES WILL BE FABRICATED AND TESTEDDURING THE SUBSEQUENT PHASE II PROGRAM.