Abstract: A wireless communication system for communicating between a host system and a stand-alone device through an electromagnetic coupling medium is disclosed. The communication system has the capabilities of bi-directional data communications between the host and the stand-alone device and of powering the stand-alone device with energy pulses coupled through the electromagnetic coupling medium from the host. The electromagnetic medium is capable of supporting the bi-directional flow of energy pulses and energy transitions thereof between the host and stand-alone device. In one embodiment, bi-directional communication is provided by transmitting and detecting predetermined numbers of consecutive energy transitions coupled through the medium. Resting durations immediately precede and follow each predetermined number of consecutive energy transitions.

Abstract: An improved EEPROM structure is disclosed which provides protection against external detection of data stored within the array's memory cells via microprobing by causing the array's word lines to de-activate upon an attempted deprocessing of the array. An EEPROM "protect" cell is connected in parallel between each word line within the array and ground potential. Each of these protect cells has formed therein one or more substantially vertical cavities filled with a high etching film. These cavities are provided in a region adjacent to an end of the protect cell's floating gate such that during an attempted deprocessing of the array using an etching process in order to expose the array's word, bit, and control lines for microprobing, the etchant will rapidly diffuse through these cavities, exposing and discharging the floating gate before fully exposing the word, bit, and control lines. Once discharged, each protect cell shorts its associated word line to ground potential.

Abstract: A wireless communication system for communicating between a host system and a stand-alone device through an electromagnetic coupling medium is disclosed. The communication system has the capabilities of bi-directional data communications between the host and the stand-alone device and of powering the stand-alone device with energy pulses coupled through the electromagnetic coupling medium from the host. The electromagnetic medium is capable of supporting the bi-directional flow of energy pulses and energy transitions thereof between the host and stand-alone device. In one embodiment, bi-directional communication is provided by transmitting and detecting predetermined numbers of consecutive energy transitions coupled through the medium. Resting durations immediately precede and follow each predetermined number of consecutive energy transitions.

Abstract: An improved EEPROM cell structure is disclosed which provides protection against external detection of data stored within the cell. One or more cavities filled with a high etching film and extending in a substantially vertical direction are provided in a region adjacent to an end of the floating gate such that during an attempted deprocessing of the cell using an etching process, the etchant will rapidly diffuse through these cavities and expose the floating gate via these cavities before exposing and removing the control gate via the insulating layers overlapping the control gate. Any charge once present on the floating gate will dissipate before the control gate can be removed, thereby making it impossible to read data stored within the cell.

Abstract: A wireless communication system for communicating between a host system and a stand-alone device through an electromagnetic coupling medium is disclosed. The communication system has the capabilities of bi-directional data communications between the host and the stand-alone device and of powering the stand-alone device with energy pulses coupled through the electromagnetic coupling medium from the host. The electromagnetic medium is capable of supporting the bi-directional flow of energy pulses and energy transitions thereof between the host and stand-alone device. In one embodiment, bi-directional communication is provided by transmitting and detecting predetermined numbers of consecutive energy transitions coupled through the medium. Resting durations immediately precede and follow each predetermined number of consecutive energy transitions.

Abstract: The endurance of ferroelectric capacitors can be extended by refreshing the ferroelectric material. The ferroelectric material is refreshed by impressing a voltage across the ferroelectric capacitor, which voltage is higher than that which the capacitor experiences during normal operation. A memory array having ferroelectric capacitive cells can be refreshed by first reading the memory cells, temporarily storing the data in associated sense amplifiers, refreshing the memory cells by impressing a higher-than-normal voltage across the ferroelectric cell capacitors, then rewriting the temporarily stored data back into the memory cells. Refresh circuits connected between the drive line and bit line common to a number of cells are driven with voltages which are higher than the memory cell experiences during normal read operations. A V.sub.cc to ground pulse train is applied to the drive line, while an inverted waveform thereof is applied to the bit line during refresh operations.

Abstract: A ferroelectric random access memory device contains columns of ferroelectric memory cells, each column of memory cells being coupled to a distinct bit line. Each memory cell is selectively coupled to a corresponding bit line by an access control transistor so that only one memory cell in the column is coupled to the bit line at a time. To read the data stored in a selected memory cell reads, the cell is strobed twice, separately sampling the output voltage generated each time. Since the first read is a destructive read, the second read operation always reads the cell in its "0" state. Then the two sampled outputs are compared, and if the first reading exceeds the second by at least a threshold amount then a "1" output value is generated. Otherwise a "0" is the output value. In a preferred embodiment, the time delay between strobing the memory cell and sampling its output is made longer the first time that the cell is read than for the second time that the cell is read.

Abstract: A ferroelectric memory device includes a preamplifier that couples a bit line to a sense amplifier. The preamplifier both provides additional bit line capacitance needed to enable full switching of the ferroelectric capacitor in a selected memory cell, and data signal amplification needed to obtain a reliable data signals from the memory cells after the memory device has aged and the ferroelectric capacitors in the memory cells are generating relatively small voltage signals. More specifically, the preamplifier of the present invention is a set of capacitors which can be switched between two configurations. In the first configuration, used while strobing a selected memory cell, the capacitors are all connected in parallel to the bit line, thereby providing the bit line capacitance needed to enable full switching of the ferroelectric capacitor in the selected memory cell.

Abstract: An integrated circuit aluminum-silicon electrical contact may be fabricated in a diffusion region formed in a monocrystalline silicon semiconductor layer by converting the upper portion of the diffusion region into an amorphous region. Alloy pitting is substantially decreased since the solubility of silicon in aluminum is highly dependent upon crystallographic orientation of the silicon and decreases as the silicon approaches an amorphous form. The amorphous region may be formed by implanting arsenic ions with an energy of at least 180 keV and a dosage of approximately 10.sup.15 ions/cm.sup.2.

Abstract: A transducer for producing a pulse duration modulated signal in accord with the value of a parameter. A reference capacitor-resistance circuit is provided having a predetermined rate of capacitor discharge and a second capacitor-resistance circuit is provided having a capacitor and a resistor, one of which is varied in accordance with the parameter to define a rate of capacitor discharge determined by the parameter. Each of the capacitors is periodically charged in unison to a predetermined voltage. Respective level detectors monitor the capacitor voltage charges and generate respective digital signals when the voltage charge monitored is greater than a predetermined reference below which each capacitor discharges during the time interval between charges. A logic circuit monitors the digital signals and produces a series of pulses having durations determined by the value of the parameter.

Abstract: A semiconductor pressure transducer having a polycrystalline silicon diaphragm providing an extremely pressure sensitive and temperature stable device, and a method of making the same. The polycrystalline silicon can easily be vapor deposited on an etch resistant layer covering a surface of a wafer or base, preferably monocrystalline silicon. Such vapor deposition of the polycrystalline silicon more accurately and consistently defines the thickness of the diaphragm than can be obtained by grinding or etching. A pressure responsive resistor formed in the diaphragm is automatically electrically isolated by the comparatively high resistivity of the polycrystalline silicon. Accordingly, PN junction isolation and passivating oxides on the diaphragm are not required thereby resulting in increased temperature stability.

Abstract: A method of making thin diaphragms having an accurately controllable thickness for semiconductor pressure responsive devices. An oxide coating is thermally grown in selected regions on the front side of a silicon wafer. The oxide extends into the wafer at an extremely accurate and controllable depth to form a groove in the wafer front side defined by the selected regions. Portions of the wafer are then etched from the back side until the bottom of the groove is reached thereby providing a diaphragm having a thickness equal to the accurately reproducible depth of the groove.

Abstract: A semiconductor pressure transducer having a polycrystalline silicon diaphragm providing an extremely pressure sensitive and temperature stable device, and a method of making the same. The polycrystalline silicon can easily be vapor deposited on an etch resistant layer covering a surface of a wafer or base, preferably monocrystalline silicon. Such vapor deposition of the polycrystalline silicon more accurately and consistently defines the thickness of the diaphragm than can be obtained by grinding or etching. A pressure responsive resistor formed in the diaphragm is automatically electrically isolated by the comparatively high resistivity of the polycrystalline silicon. Accordingly, PN junction isolation and passivating oxides on the diaphragm are not required thereby resulting in increased temperature stability.