Abstract: An electrostatic discharge device having a small separation between two traces wherein a voltage above a desired threshold will discharge across the separation through the mechanism of cold cathode electric field emission. Conditions which permit quantum mechanical tunneling of electrons across the emitting cathode/vacuum potential barrier, such as low emitter work function, electric field enhancing geometry, and cathode/anode separation size, determine the voltage necessary for discharge by this mechanism. One device has a first conductive trace formed on an insulating layer and then masked and etched to leave an undercut with a sharp point. A second conductive trace is formed in the undercut opposite the point, resulting in a three-dimensional cross section having a very small separation. A second device has the point formed by depositing a metal layer over a spacing in a dielectric layer, and then etching out the dielectric layer.

Abstract: An electrostatic discharge device having a small separation between two traces wherein a voltage above a desired threshold will discharge across the separation through the mechanism of cold cathode electric field emission. Conditions which permit quantum mechanical tunneling of electrons across the emitting cathode/vacuum potential barrier, such as low emitter work function, electric field enhancing geometry, and cathode/anode separation size, determine the voltage necessary for discharge by this mechanism. One device has a first conductive trace formed on an insulating layer and then masked and etched to leave an undercut with a sharp point. A second conductive trace is formed in the undercut opposite the point, resulting in a three-dimensional cross section having a very small separation. A second device has the point formed by depositing a metal layer over a spacing in a dielectric layer, and then etching out the dielectric layer.

Abstract: A method for fabricating a solid state semiconductor gas sensor and the semiconductor sensor itself for use in equipment detecting small amounts of H.sub.2 S. The method of sensor fabrication comprises spray deposition of a mixture of metal oxides mixed together with various metal and non-metal materials which serve in the finished product as activators, dopants, and/or film binder materials, and including in suspension a molecular sieve material, for enhancing porosity on a scale of molecular dimensions in the finished sensor. All of the foregoing materials are suspended in a suitable solution and preferably sprayed onto a heated insulating substrate to form the finished product. The example sensor, capable of selective detection of H.sub.2 S in air and a sensitivity of less than 1 PPM (part per million), is comprised of a platinum activated alumina, tin oxide, and zeolite molecular sieve material.

Abstract: A semiconductor gas sensor for use in equipment for detecting small amounts of H.sub.2 S. The method of sensor fabrication comprises spray deposition of a mixture of metal oxides mixed together with various metal and non-metal materials which serve in the finished product as activators, dopants, and/or film binder materials, and including in suspension a molecular sieve material, for enhancing and defining porosity on a scale of molecular dimensions in the finished sensor. All of the foregoing materials are suspended in a suitable solution and preferably sprayed onto a heated insulating substrate to form the finished product. The example sensor, capable of selective detection of H.sub.2 S in air and a sensitivity of less than 1 PPM (part per million), is comprised of a platinum activated alumina, tin oxide, and zeolite molecular sieve material.

Abstract: A pair of electrodes are spaced apart on an electrically-insulating support surface. Disposed on the surface in a position bridging the electrodes is a sensor that exhibits a change in conductivity in response to exposure of the material to a wide variety of certain flammable and toxic gases. Overlying the sensor is a molecular sieve passivation layer composed of a porous solid material that has a pore size no larger than the molecular size of the gas to be sensed. The molecular sieve passivation layer can be incorporated onto various solid state and catalytic-type gas sensors, including metal oxide based solid-state sensors such as, for example, those of a zinc oxide base. With or without the sieve, the most salient form of zinc oxide based sensor is zinc oxide doped with gallium oxide. It is expedient to use such improved sensors as a discrete device or in a hybrid array for environmental ambient qualification as incorporated into a portable instrument.