OVONIC THRESHOLD SWITCH (OTS) FOR EMP PROTECTION OF MEDICAL ELECTRONIC EQUIPMENT

A DEVELOPMENT PROGRAM IS DESCRIBED WHICH WILL CONFIRM THE FEASIBILITY OF THE OVONIC THRESHOLD SWITCH (OTS) TO PROTECT ELECTRONIC SYSTEMS FROM EMP OR OTHER ELECTROMAGNETIC DISTURBANCES. THE DEVICE WILL BE INVESTIGATED FOR THE CASE OF VERY LARGE ELECTRODE AREAS IN ORDER TO CONFIRM AN EXPANDING CHANNEL MODEL WHICH ALLOWS FOR VERY HIGH CURRENT CARRYING CAPABILITY. THE KEY TECHNICAL ISSUES FOR THE LARGE ELECTRODECASE ARE: 1) THE CAPABILITY OF THE OTS TO ABSORB THE ENERGY FROM THE CAPACITIVE DISCHARGE; 2) THE ABILITY OF THE OTS TO PROVIDE NANOSECOND SWITCHING SPEEDS AT THE VERY HIGH CURRENT LEVELS; 3) THE CAPABILITY OF THE OTS TO OPERATE OVER A WIDE TEMPERATURE RANGE. TONC (TRANSIENT ON-STATE CHARACTERISTICS) EXPERIMENTS WILL BE EMPLOYED AS THE PRIMARY ELECTRICAL CHARACTERIZATION METHODOLOGY. OPERATION OF THE DEVICE WILLBE MEASURED AT TEMPERATURES UP TO 125 DEGREES CENTIGRADE, AND DATA FOR 2000 HOURS OF SHELF LIFE AT 10 DEGREES CENTRIGRADE BELOW THE RECRYSTALLIZATION TEMPERATURE WILL ALSO BE ACQUIRED. A FULL RANGE OF MATERIALS ANALYSIS EQUIPMENT WILL BE UTILIZED TO SUBSTANTIATE PROPOSED DEVICE MODELS AND TO IDENTIFY SPECIFIC FAILURE MODES.