摘要:
A new flash memory cell structure and operational bias is based on the use of a triple well flash memory cell which allows pre-programming by Fowler Nordheim (F-N) tunneling over blocks of cells at a time. The floating gate memory cell is made in a semiconductor substrate having a first conductivity type, such as p-type. A first well within the substrate by having a second conductivity type different than the first conductivity type is included. A second well within the first well is also included having the first conductivity type. A drain and a source are formed in the second well having the second conductivity type, and spaced away from one another to define a channel area between the drain and the source. A floating gate and control gate structure is included over the channel area. The floating gate memory cell is coupled with circuits that induce F-N tunneling of electrons out of the floating gate into the channel area of the substrate for erasing by applying a positive voltage to the second well, such as a voltage higher than the supply voltage, applying a positive voltage to the first well, which is substantially equal to the positive voltage of the second well, applying a negative voltage to the control gate of the cell, while the substrate is grounded. A block wide pre-program operation involves F-N tunneling of electrons into the floating gate from the channel area, using a negative voltage in the second well.
摘要:
A method of manufacturing integrated circuits based on providing a test column of memory cells in the devices. Cells in the test column are selected by a portion of the addresses which identifies a row in the main array on the device. A test is executed to determine a characteristic of the device, and the results of that test are mapped to the portion of the address which identifies a row in the array. This produces a characteristic code address for the device which indicates the results of the test. Access to the test column on the device is enabled, and a bit is written in response to the characteristic code address in a memory cell on the test column. During manufacture the test column is read in order to classify the device according to the characteristic. This allows for storing in a table look-up format, significant amounts of data about the characteristics of the device without requiring large amounts of memory on the device, and substantially relieving the testing system of a requirement for memory resources.
摘要:
A new flash memory cell structure and operational bias is based on the use of a triple well flash memory cell which allows Fowler Nordheim (F-N) tunneling with lower absolute value bias potentials. Thus, the floating gate memory cell is made in a semiconductor substrate having a first conductivity type, such as p-type. A first well within the substrate by having a second conductivity type different than the first conductivity type is included. A second well within the first well is also included having the first conductivity type. A drain and a source are formed in the second well having the second conductivity type, and spaced away from one another to define a channel area between the drain and the source. A floating gate and control gate structure is included over the channel area. The floating gate memory cell is coupled with circuits that induce F-N tunneling of electrons out of the floating gate into the channel area of the substrate for erasing by applying a positive voltage to the second well, such as a voltage higher than the supply voltage, applying a positive voltage to the first well, which is substantially equal to the positive voltage of the second well, applying a negative voltage to the control gate of the cell, while the substrate is grounded. A block wide pre-program operation involves F-N tunneling of electrons into the floating gate from the channel area, using a negative voltage in the second well. Also, circuits are coupled with the cell to induce hot electron injection current of electrons into the floating gate for programming or byte by byte preprogramming.
摘要:
A flash memory device includes a multiple checkpoint erase suspend algorithm. A user may issue an erase suspend command at anytime during an erase process. The erase procedure is suspended as fast as possible by allowing the erase procedure to be suspended at the first to occur of a plurality of checkpoints in the process. The block erase procedure includes a precondition phase (also called a pre-programming phase), in which a selected block is pre-programmed by applying a program potential, and then the pre-programming of the block is verified on a byte-by-byte basis. After the precondition phase, an erase phase is executed in which the selected block is erased by applying an erase potential to the block, and then verifying the erasing of the block. Erase suspend logic is coupled to the erase logic and executes an erase suspend procedure which interrupts the block erase procedure after receiving the erase suspend command during the first to occur of a set of checkpoints in the block erase procedure. The set of checkpoints comprises a first checkpoint enabling the interrupting during the precondition phase, a second checkpoint enabling the interrupting during the application of the erase potential, a third checkpoint enabling the interrupting during the verifying of the erasing step, a fourth checkpoint between the precondition phase and the erase phase, and a fifth checkpoint after the erase pulse and before verifying the erase of the block. After interrupting the block erase procedure, the erase suspend procedure includes returning to the block erase procedure to complete the block erase.
摘要:
A floating gate memory device which includes control circuits to generate a repair pulse to repair over-erased cells so they may be repaired block-by-block. This invention includes repairing the cells by applying a repair pulse to the cell's bit line while maintaining the word line voltage above ground. In a different embodiment, the word line voltage is maintained at two different voltage levels above ground. In the first stage, the word line voltage is maintained between approximately 0.1 volts and 0.2 volts for approximately 100 ms while the repair pulse is applied. In the second stage, the word line voltage is maintained between approximately 0.4 volts and 0.5 volts for approximately 100 ms while the repair pulse is applied.
摘要:
In one aspect, a first charge pump has serially arranged charge pump stages. Inter-stage nodes between adjacent stages are pumped by a second charge pump. In another aspect, timing of the charge pump stages is controlled by at a command clock signal. The command clock signal and command data are communicated between a integrated circuit with the charge pump and an external circuit.
摘要:
A single-poly two-transistor PMOS memory cell for multiple-time programming applications includes a PMOS floating gate transistor sharing a drain/source P+ diffusion region with a PMOS select gate transistor all formed within a first n-well. A control plate for the floating gate transistor is formed in a second n-well. A single-poly two-transitor PMOS memory cell for one-time programming applications includes a PMOS floating gate transistor having a source formed as a p+ diffusion region in a single n-well. The source is adapted to also serve as control plate for the floating gate transistor.
摘要:
In one aspect, a first charge pump has serially arranged charge pump stages. Inter-stage nodes between adjacent stages are pumped by a second charge pump. In another aspect, timing of the charge pump stages is controlled by at a command clock signal. The command clock signal and command data are communicated between a integrated circuit with the charge pump and an external circuit.
摘要:
A single-poly two-transistor PMOS memory cell for multiple-time programming applications includes a PMOS floating gate transistor sharing a drain/source P+ diffusion region with a PMOS select gate transistor all formed within a first n-well. A control plate for the floating gate transistor is formed in a second n-well. A single-poly two-transitor PMOS memory cell for one-time programming applications includes a PMOS floating gate transistor having a source formed as a p+ diffusion region in a single n-well. The source is adapted to also serve as control plate for the floating gate transistor.
摘要:
A single-poly two-transistor PMOS memory cell for multiple-time programming applications includes a PMOS floating gate transistor sharing a drain/source P+ diffusion region with a PMOS select gate transistor all formed within a first n-well. A control plate for the floating gate transistor is formed in a second n-well. A single-poly two-transitor PMOS memory cell for one-time programming applications includes a PMOS floating gate transistor having a source formed as a p+ diffusion region in a single n-well. The source is adapted to also serve as control plate for the floating gate transistor.