INSTRUMENT FOR ELECTRICAL SURFACE CHARACTERIZATION DURING PROCESSING

DESCRIBED IS AN INSTRUMENT FOR MONITORING THE WORK FUNCTION OF SURFACES DURING SURFACE PROCESSING. THE INSTRUMENT MEASURES THE CONTACT POTENTIAL DIFFERENCE BETWEEN THE SURFACE AND AN INERT REFERENCE ELECTRODE BY A VARIABLE CAPACITANCE TECHNIQUE. A NOVEL METHOD FOR CAPACITANCE MODULATION BETWEEN THE UNKNOWN AND THE REFERENCE ELECTRODE IS USED. THE MEASUREMENT CAN BE DONE IN VACUUM OR AMBIENT GAS. THE PROBE DESIGN WOULD ALLOW IT TO BE MOVED AWAY DURING SAMPLE ANNEALING, OR OVER-COATING OF THE SAMPLE SURFACE, AND THEN REPOSITIONED FOR MEASUREMENT. PROVISION CAN BE MADE TO CLEAN OR REMOVE SAMPLE SURFACE LAYERS IN ORDER TO EXPOSE FRESH BULK MATERIAL. SPECIFICALLY, THE INSTRUMENT IS DESIGNED TO MONITOR CHANGES IN THE SURFACE ELECTRICAL PROPERTIES OF HIGH TC OXIDE SUPERCONDUCTORSTHAT ARE BEING PROCESSED FOR SQUIDS AND RF CAVITY STRUCTURES. THE INSTRUMENT IS ALSO SUITABLE FOR MONITORING SEMICONDUCTOR SURFACES DURING PROCESSING.