Abstract: A chemically sensitive field effect device has its chemically selective system exposed to the material being investigated. The device is driven by a time varying, typically sinusoidal, current source. A protected reference electrode is also in contact with the body under investigation, and is biased at a predetermined DC level relative to the chemically sensitive field effect device.

Abstract: A polarographic sensor for blood oxygen monitoring is defined by respective anode and cathode electrode wires fixedly maintained in conventional fashion. The end cross sections of the wires are carried on a surface, and overlying this surface is a capillary pore ultrafiltration membrane. The microscopic capillary pores, which have diameters less than 12 micrometers each, pass water therethrough and thus allow the blood, which passes on the side of the membrane opposite the anode and cathode, to act as its own electrolyte.

Abstract: Semiconductor chips carrying chemically sensitive field effect devices are encapsulated by tape automated bonding techniques, wherein one tape layer has a beam lead pattern disposed thereon which terminates in the chip bonding pad pattern over an opening in the tape. A tape layer for sealably covering the beam lead pattern and the chip has openings which are respectively coincident with the chemically selective membrane systems of the field effect devices.

Abstract: A system for encapsulating semiconductor chips, such as chips carrying chemical sensitive field-effect devices, includes lamination of a sheet of dry film photoresist material onto the surface of the chip, placement of a photomask over the chip in a predetermined alignment, and then exposure of the photomask to light so that light passes through certain light-transmitting portions of the mask onto the chip. The photoresist material is then developed to remove the material from over the gate regions of each of the field-effect devices to define windows in the material through which the gate regions are exposed. Chemical sensitive membrane systems may then be applied to the windows of the devices to cover the gate regions.