Silicon Storage Technology, Inc.

Xilinx, Inc.

Cypress Semiconductor Corporation

Integrated Memory Technologies, Inc.

Ben Y Sheen

Jonathan Pabustan

Prateep Tuntasood

Farshid Shokouhi

Geeng-Chuan Chern

Michael G Ahrens

Der-Tsyr Fan

Qi Lin

Yaw Wen Hu

Timothy M Lacey

Sammy S Cheung

Tien L Lin

Chih-Chieh Wang

Tseng-Yi Liu

A flash memory cell is of the type having a substrate of a first conductivity type having a first region of a second conductivity type at a first end, and a second region of the second conductivity type at a second end, spaced apart from the first end, with a channel region between the first end and the second end. The flash memory cell has a plurality of stacked pairs of floating gates and control gates with the floating gates positioned over portions of the channel region and are insulated therefrom, and each control gate over a floating gate and insulated therefrom. The flash memory cell further has a plurality of erase gates over the channel region which are insulated therefrom, with an erase gate between each pair of stacked pair of floating gate and control gate. In a method of erasing the flash memory cell, a pulse of a first positive voltage is applied to alternating erase gates ('first alternating gates'). In addition, a ground voltage is applied to erase gates other than the first alternating gates ('second alternating gates'). In a second method to erase the flash memory cell, a pulse of a first positive voltage is applied to the first alternating gates and a negative voltage is applied to the second alternating gates and to all control gates.

Method for erasing a flash memory cell or an array of such cells having improved erase coupling ratio

Redundantly repaired semiconductor memory and method in which the configuration data for the memory is stored in an area of the main memory array which is known to be free of bad bits, along with a signature code which serves as a pointer and verifies the validity of the configuration data. In one disclosed embodiment, the data is stored in a configuration memory which is divided into a plurality of areas of equal size and known starting addresses. The number of areas is greater than the number of permitted repairs, and the areas which do not contain defects are available for storing configuration data including device settings, repair information, and the like.

Semiconductor memory and method of storing configuration data

The present invention relates to a method of a programming a select non-volatile memory cell in a plurality of serially connected non-volatile memory cells with a serially connected select transistor. Each of the non-volatile memory cells has a control gate for receiving a programming voltage and the select transistor has a select gate for receiving a select voltage. The method comprises applying the programming voltage to the control gate of the select non-volatile memory cell in a program command sequence. The magnitude of the select voltage to the select gate of the select transistor within the program command sequence is then varied. The method can be applied to non-volatile cells in a NAND or NOR architecture.

Method of programming a non-volatile memory cell

A memory array has a plurality of memory cells, arranged in a plurality of rows and columns. Each cell has at least four terminals. The array has a plurality of column lines with each column line connected to a first terminal of a different column of cells. The array also has a plurality of first row lines, with each first row line connected to a second terminal of a different row of cells. The array also has a plurality of second row lines, with each second row line connected to a third terminal of a different row of cells. Finally, the array has a plurality of third row lines with each third row line connected to a fourth terminal of a different row of cells. A column decoder is connected to the plurality of column lines. A first row decoder is connected to the plurality of first row lines. A second row decoder is connected to the plurality of second row lines. A third row decoder is connected to the plurality of third row lines. During an operation of a selected cell, the column decoder selects one of the plurality of column lines, with the one column line selected connected to the first terminal of the selected cell. The first row decoder selects one of the plurality of first row lines with the one first row line selected connected to the second terminal of the selected cell. The second row decoder selects a first plurality of second row lines, with one of the first plurality of second row lines connected to the third terminal of the selected cell. The third row decoder selects a second plurality of third row lines, with one of the second plurality of third row lines connected to the fourth terminal of the selected cell. Finally, the first plurality of second row lines, other than the one second row line, are connected to cells arranged in rows other than rows of cells to which the second plurality of third row lines are connected. The interconnection minimizes programming disturbance.

Method and apparatus for reducing operation disturbance

The present invention provides a tunable circuit for quickly optimizing an electrical field generated by the F-N tunneling operation. To optimize this electrical field, the charging of a positive charge pump is begun after the charging of a negative charge pump. The tunable circuit of the present invention provides a means to detect the optimal negative voltage at which pumping of the positive voltage should begin. The tunable circuit includes a resistor chain coupled between a first reference voltage and a negative voltage from the negative charge pump. When charging of the negative charge pump begins, a comparator compares the voltage at a node within the resistor chain to a second reference voltage. In accordance with the present invention, the node voltage within the resistor chain is equal to the second reference voltage when the negative voltage is equal to the voltage to be detected. Thus, the comparator generates a trigger signal when the voltage at the node decreases to the second reference voltage. This output signal triggers the pumping of the positive charge pump. By changing the resistance within the resistor chain, the positive charge pumping may be initiated at varying negative voltages. In the present invention, additional resistance is added to or removed from the resistor chain via metal options or switches.

Tunable circuit for detection of negative voltages

The present invention provides a tunable circuit for quickly optimizing an electrical field generated by the F-N tunneling operation. To optimize this electrical field, the charging of the positive charge pump is begun after the charging of the negative charge pump. The tunable circuit of the present invention provides a means to detect the optimal negative voltage at which pumping of the positive voltage should begin. The tunable circuit includes a resistor chain coupled between a first reference voltage and a negative voltage from a negative charge pump. When charging of the negative charge pump begins, a comparator compares the voltage at a node within the resistor chain to a second reference voltage. In accordance with the present invention, the node voltage within the resistor chain is equal to the second reference voltage when the negative voltage is equal to the voltage to be detected. Thus, the comparator generates a trigger signal when the voltage at the node decreases to the second reference voltage. This output signal triggers the pumping of the positive charge pump. By changing the resistance within the resistor chain, the positive charge pumping may be initiated at varying negative voltages. In the present invention, additional resistance is added to or removed from the resistor chain via metal options or switches.

A shift register system is disclosed wherein shift registers buffering memory data perform shift operations in response to a set of sub-clock signals. The set of sub-clock signals comprise nested sub-clock signals having non-overlapping transitions formed from a system clock signal or power on reset signal. Each shift register (or bank of shift registers) responds to a different sub-clock signal. As a result, shift operations are spread out over a period of time rather than occurring simultaneously. Thus, the current drawn during each shift operation is similarly spread out over a period of time. The maximum current drawn during any one shift operation is inversely proportional to the number of non-overlapping sub-clock signal. Therefore, the maximum current drawn (i.e., current spike) drawn during memory operations is minimized.

Shift register clock scheme

A floating gate memory device that includes a switching circuit for selectively transferring two or more negative voltages to a common node (e.g., to the negative pole of a driver circuit). The switching circuit includes two switches respectively connected between the two negative voltages and the common node. Each of the switches includes series-connected triple-well NMOS transistors that provide a dual-isolation structure between the common node the negative voltage sources. An optional triple P-well resistor is provided between the series-connected triple-well NMOS transistors in each of the switches that includes a deep N-well region biased by a system voltage source (e.g., VCC) to reverse bias the central P-well region.

Switching circuit for transference of multiple negative voltages

A novel flash memory array has an array of memory cells with each memory cell being of a floating gate memory transistor with a plurality of terminals. The memory cells are arranged in a plurality of rows and a plurality of columns, with a word line connecting the memory cells in the same row. A row decoder is positioned adjacent one side of the memory array and is connected to the plurality of word lines for receiving an address signal and for supplying a low voltage signal. A plurality of programming lines are connected to the plurality of rows of memory cells of the array with a programming line connected to the memory cells in the same row. The plurality of programming lines are collinear with but spaced apart from the plurality of word lines and extending only to the row decoder. A high voltage generating circuit is positioned adjacent the other side of the array, opposite the one side, and connected to the plurality of programming lines for receiving the address signal and for supplying a high voltage signal to the plurality of programming lines in response thereto.

Flash memory array

A pseudo-differential sense amplifier for sensing the state of an array memory cell by reference to a reference cell in a predetermined state. The sense amplifier has an input stage coupled to the array memory cell, which provides signals to a differential stage from which an output is generated. The input stage has reference and array side cascode circuits in which the components are matched on each side so as to eliminate process, temperature, and other extraneous variations from influencing the differential output. An enabling signal to the array side of the input stage is delayed with respect to the reference side such that voltage fluctuations externally introduced into the signals passed from the input stage to the differential stage do not cause erroneous switching and/or glitches to appear at the sense amplifier output. Additionally, parallel cascode and load transistors can be selectively switched into the input stage circuit to enable selectable cascode transconductance and circuit loading to effect selectable speed and/or input stage voltage swing.

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Milpitas, CA, United States of America

Ben Y Sheen