National Semiconductor Corporation

Monolithic Memories, Inc.

Other

Ury Priel

Allen H Frederick

Jerry D Gray

Giora Yaron

Mark S Ebel

William E Moss

Ronald C Laugesen

Ying K Shum

Jayasimha S Prasad

Shlomo Waser

Robert A Anselmo

A means for testing the threshold voltage changes in a programmable and erasable floating gate memory cell by accessing directly and exclusively the cells in the core, and the amplifiers that sense the operation of the cells, so as to measure the relative currents therein as an indication of threshold voltage parameters.

Memory core testing system

An electrically programmable and eraseable memory cell in which charge carriers are tunnelled between a floating gate and a drain region in the substrate through a thin oxide tunnel region, the borders of said tunnel region being confined to a small area well inside the borders of both the drain region and the floating gate. Dual paths are utilized to connect the tunnel region of the gate to the memory cell region of the gate.

Electrically programmable and erasable memory cell

A circuit for clearing selected bytes in a semiconductor electrically alterable memory in which the ground lines for any one column of bytes is isolatable from the ground lines for other columns, all the outputs for the bytes are urged toward a non-clearing condition, and the outputs for only the selected byte are used to introduce a clearing signal that dominates the non-clearing condition.

Semiconductor memory byte clear circuit

A bidirectional serially controlled programmable read-only memory has a serial input/output (I/O) port and a parallel I/O port. By selecting the appropriate control inputs, the instant invention can receive serial address or data information and output data to either the parallel or serial I/O ports. In a like manner, an address at the parallel I/O port can be utilized to generate output data in either a serial or parallel form. In general, the parallel I/O port will be utilized to transfer data to and from a microprocessor, whereas the serial I/O port will be utilized to transfer data to and from an external interface. By proper utilization of the control circuits and appropriate use of the control signals, data may be read from the bidirectional PROM in parallel form from the parallel I/O port or in serial form from the serial I/O port. In addition, data may be transferred from the serial I/O port to the parallel I/O port or from the parallel I/O port to the serial I/O port. Multiplexing means and register means interact with the control circuits to formulate the data transfers.

Bidirectional dual port serially controlled programmable read-only memory

Shallow, boron implanted regions are formed by ion implanting. Disclosed is a PNP transistor device (lateral type) having a P type emitter region preferably made with a boron implant.

Lateral PNP transistor

Two output voltages are generated in response to the output of a power supply. One output is referenced to the positive supply terminal V.sub.CC and the other output is referenced to the negative supply terminal V.sub.EE.. A first .DELTA.V.sub.BE reference circuit provides for the production of the pair of voltages which are temperature compensated. A second .DELTA.V.sub.BE reference circuit operates a voltage regulator which supplies the first .DELTA.V.sub.BE reference. The resulting two output voltages are temperature compensated and substantially independent of power supply voltage variations.

Fixed voltage reference circuit

This disclosure relates to a low power write-once, read-only semiconductor memory (PROM or programmable read only memory) array wherein the semiconductor resistors located in the word line decoder and driver and also in the bit line decoder and sense amplifier of the memory array are fabricated to have a high resistivity thereby permitting the semiconductor array to operate with much lower power. The high resistivity semiconductor resistors of this write-once, read-only semiconductor memory array are fabricated using an ion implantation step, preferably, between the base and emitter diffusion process steps in fabricating the NPN transistor structures used in the bit line and word line decoders of the memory array. The high resistivity ion implanted resistor regions are preferably shallow, boron implanted regions that are formed by ion implanting through a thin silicon dioxide layer. Various resistor devices are disclosed using shallow, boron implanted, high resistivity regions. Also disclosed are PNP transistor devices (both vertical and lateral types) having P type emitter regions preferably made with a Boron implant. A P-channel MOS device is also disclosed where the P+ source and drain regions are shallow, implanted regions.

High resistivity semiconductor resistor device

Fabrication of high resistivity semiconductor resistors by ion

This disclosure relates to a low power write-once, read-only semiconductor memory (PROM or programmable read only memory) array wherein the semiconductor resistors located in the word line decoder and driver and also in the bit line decoder and sense amplifier of the memory array are fabricated to have a high resistivity thereby permitting the semiconductor array to operate with much lower power. The high resistivity semiconductor resistors of this write-once, read-only semiconductor memory array are fabricated using an ion implantation step, preferably, between the base and emitter diffusion process steps in fabricating the NPN transistor structures used in the bit line and word line decoders or the memory array. The high resistivity ion implanted resistor regions are preferably shallow, boron implanted regions that are formed by ion implanting through a thin silicon dioxide layer. Various resistor devices are disclosed using shallow, boron implanted, high resistivity regions. Also disclosed are PNP transistor devices (both vertical and lateral types) having P type emitter regions preferably made with a boron implant. A P-channel MOS device is also disclosed where the P+ source and drain regions are shallow, implanted regions.

Low power write-once, read-only memory array

In order to increase the output current of an MOS transistor, its gate is provided with a switched capacitor drive. A tri-state inverter is used to drive the output transistor gate from an input source. A pair of delay elements are cascaded to drive one input of a NOR gate, the other input of which is fed an undelayed signal. The NOR gate is used to switch a capacitor that is also coupled to the output transistor gate. The juncture between the delays is coupled to the control electrode of the tri-state inverter. During the first delay interval, the capacitor and the output transistor gate electrode are charged. Then after the second delay interval, which is shorter than the first, the capacitor is discharged into the output transistor gate electrode which is thereby driven substantially in excess of the conventional drive level.

Circuit for increasing the output current in MOS transistors

A novel sense amplifier circuit providing conversion of MOS input signals to TTL output signals with tri-state logic output at the output data bus, the input circuit of the sense amplifier providing current sensing and programmable input thresholds for economical construction and enhanced speed of operation of the sense amplifier. A novel tri-state operation is provided for the input section of the sense amplifier to provide either a clamped voltage at the input data bus line during MOS to TTL communication or a floating input when it is desired that MOS devices on the input data bus are to communicate.

Sense amplifier with tri-state bus line capabilities

A dual inverter circuit wherein the first inverter circuit includes a pair of phase splitter transistors, one serving to feed the base of the pull-up transistor in the first inverter circuit and the other serving to feed the base of the phase splitter transistor in the second inverter circuit. The circuit provides a minimum delay time between the operation of the first inverter and the turn-on time of the second inverter while also providing active pull-up circuits, i.e., pull-up transistors, in the two inverters to insure fast operate times for both inverters especially desirable when feeding into large capacitance loads.

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Cupertino, CA, United States of America

Ury Priel