Abstract: A nonvolatile memory cell comprising a pair of spaced apart shallow trench isolation regions formed in a substrate and defining a substrate active region. A tunnel dielectric is formed on the substrate active region. A floating gate is formed on the tunnel dielectric and is self aligned between the spaced apart shallow trench isolation regions. A dielectric layer is formed on the floating gate and a control gate formed on the dielectric layer. A source region and a drain region are formed in the substrate active region on opposite sides of the floating gate.

Abstract: A nonvolatile memory cell comprising a pair of spaced apart shallow trench isolation regions formed in a substrate and defining a substrate active region. A tunnel dielectric is formed on the substrate active region. A floating gate is formed on the tunnel dielectric and is self aligned between the spaced apart shallow trench isolation regions. A dielectric layer is formed on the floating gate and a control gate formed on the dielectric layer. A source region and a drain region are formed in the substrate active region on opposite sides of the floating gate.

Abstract: A method and circuitry for programming a memory cell to one of at least three amounts of charge. The amount of charge placed in the memory cell is increased by increasing the voltage level of a programming pulse applied to the memory cell.

Abstract: A method and circuitry for programming a memory cell to one of at least three amounts of charge. The amount of charge placed in the memory cell is increased by increasing the voltage level of a programming pulse applied to the memory cell.

Abstract: Methods and apparatus for determining the state of a memory cell having more than two possible states are disclosed. For a first embodiment, the state of a flash cell having n states, where n is a power of 2, is determined by selectively comparing the threshold voltage V.sub.t of a selected memory cell to (n-1) reference voltages. For every two states, a single comparator is provided such that the total number of comparators is equal to the number of bits stored in the memory cell.

Abstract: A method of programming a flash memory cell. The method occurs in a memory device having a decoder that receives a select signal. The decoder is coupled to a first word line and a second word line. The first word line is coupled to a first memory cell and the second word line is coupled to a second memory cell. The select signal is asserted to a first voltage such that the decoder selects the first word line and the first memory cell and deselects the second word line and the second memory cell. The select signal is then asserted to a second voltage such that the decoder couples a programming voltage to the first word line and floats the second word line. The first memory cell is then programmed while the second word line is floating.

Abstract: Methods and apparatus for determining the state of a memory cell having more than two possible states are disclosed. For a first embodiment, the state of a flash cell having n states, where n is a power of 2, is determined by selectively comparing the threshold voltage V.sub.t of a selected memory cell to (n-1) reference voltages. For every two states, a single comparator is provided such that the total number of comparators is equal to the number of bits stored in the memory cell.

Abstract: A method for determining data stored by a memory cell. The memory cell has a select gate coupled to a wordline, a first electrode coupled to a bitline, and a second electrode coupled to a conductor. The method comprises: floating the bitline; applying a first voltage to the wordline; applying a second voltage to the conductor such that the bitline is set to a third voltage that is equal to the first voltage minus a threshold voltage of the memory cell; and sensing the third voltage to determine the data stored by the memory cell.

Abstract: A method for programming an array of memory cells, wherein each memory cell has at least three possible states. The method comprises the steps of 1) analyzing a set of data to be programmed into the array of memory cells to determine destination states for each of the memory cells in the array, and 2) programming all memory cells to be programmed to a particular destination state, up to a maximum number of memory cells being programmed at any given time, until all memory cells having a particular destination state are programmed, whereupon all memory cells to be programmed to a next destination state are programmed in a like manner.

Abstract: A method for programming a memory cell having more than two possible states to a desired state. The method includes applying a programming pulse to the memory cell. The change in the amount of charge stored by the memory cell caused by applying the programming pulse to the memory cell is sensed. The control engine determines characterization information indicative of programming characteristics of the memory cell in response to the detected change in the amount of charge stored by the memory cell. The control engine then uses the characterization information to directly program the memory cell to approximately the desired state without performing a program verify operation.

Abstract: In a memory device including an array of memory cells, each memory cell having more than two possible states, a method for programming a memory cell to a desired state. The method comprises a control engine programming a subset of the array of memory cells. Characterization information is determined from the step of programming the subset, wherein the characterization information indicates programming characteristics of a representative memory cell of the array of memory cells. The control engine then uses the characterization information to directly program the memory cell to approximately the desired state without performing a program verify operation.

Abstract: A method for programming an array of memory cells wherein each cell may be placed in more than two states. The method comprises the steps of 1) selecting a plurality of different programming voltage levels wherein each programming voltage level is associated with a corresponding one of a plurality of states, and 2) applying a plurality of programming pulses to selected subsets of the array of memory cells, wherein each programming pulse has one of the programming voltage levels and one of a corresponding plurality of pulse widths such that each of the memory cells of a corresponding one of the selected subsets are programmed directly to a corresponding one of the plurality of states by a corresponding programming pulse.

Abstract: A method and circuitry for programming a memory cell to one of at least three amounts of charge. The amount of charge placed in the memory cell is increased by increasing the voltage level of a programming pulse applied to the memory cell.

Abstract: A voltage regulation circuit that includes a sample and hold circuit for sampling an input voltage and for holding a reference voltage generated in response to the input voltage. The sample and hold circuit includes a capacitor that holds the reference voltage. The voltage regulation circuit also includes a regulator circuit coupled to the capacitor of the sample and hold circuit. The regulator circuit outputs an output voltage using the reference voltage supplied by the capacitor. The voltage regulation circuit may be used to provide a high precision programming voltage for programming memory cells having two or more analog states.

Abstract: A programming verify circuit for controlling the memory cells to which programming voltages are applied, the circuit including a comparator for testing the state of each cell being programmed with the state to which the cell is being programmed, and a program load circuit which responds to the result of the test by the comparator to hold a condition for each memory cell being programmed to indicate whether the memory cell should be further programmed, each program load circuit including circuitry for precluding the holding of a condition indicating further programming is necessary once the associated memory cell has been initially verified as programmed by the comparator.

Abstract: A method and apparatus for sensing the state of floating gate memory cells in a memory array. Because of its stability and accuracy, the sensing apparatus may be used for sensing the state of multi-bit floating gate memory cells. The state of a memory cell is sensed by applying a variable gate voltage to the top gate of the floating gate memory cell and comparing the cell current to a fixed reference current. A circuit detects when the cell current is equal to the reference current. When the currents are equal, the value of the variable gate voltage indicates the state of the memory cell. For one embodiment, an analog-to-digital converter converts the variable gate voltage to a digital value that is latched when the currents are equal. The latched digital value indicates the state of the memory cell. For this embodiment, a ramp voltage or other suitable variable voltage may be used as the variable gate voltage.

Abstract: A voltage regulation circuit that includes a sample and hold circuit for sampling an input voltage and for holding a reference voltage generated in response to the input voltage. The sample and hold circuit includes a capacitor that holds the reference voltage. The voltage regulation circuit also includes a regulator circuit coupled to the capacitor of the sample and hold circuit. The regulator circuit outputs an output voltage using the reference voltage supplied by the capacitor. The voltage regulation circuit may be used to provide a high precision programming voltage for programming memory cells having two or more analog states.

Abstract: A method of utilizing circuitry including error detecting and correcting circuitry to detect and correct errors which can occur in data stored in multi-bit per cell format in a flash EEPROM memory array before those errors can affect the accuracy of data provided by a flash EEPROM memory array.

Abstract: An integrated circuit which provides an arrangement by which the source of voltage for erasing the flash EEPROM memory array is detected and, if the source is a charge pump, the current provided is held to a constant lower value while, if the source is an external high voltage source, then the current is allowed to flow freely without regulation except by the size of a field effect transistor device in the path from the source of voltage to the memory array. In this manner, the circuitry is adapted to function with either internal or external power sources without paying a performance penalty for either type of operation.

Abstract: An integrated circuit which provides an arrangement by which the source of voltage for erasing the flash EEPROM memory array is detected and, if the source is a charge pump, the current provided is held to a constant lower value while, if the source is an external high voltage source, then the current is allowed to flow freely without regulation except by the size of a field effect transistor device in the path from the source of voltage to the memory array. In this manner, the circuitry is adapted to function with either internal or external power sources without paying a performance penalty for either type of operation.