Abstract: A method of erasing a flash electrically erasable read only memory (EEPROM) device composed of a plurality of memory cells includes pre-programming the plurality of memory cells, applying an erase pulse to the plurality of memory cells followed by an erase verification. The erase verification is followed by soft programming any memory cells having a threshold voltage below a predetermined minimum level and applying a positive gate stress to the plurality of memory cells. The erase method prevents overerasing and provides a tightened threshold voltage distribution.

Abstract: A non-volatile memory read circuit having adjustable current sources to provide end of life simulation. A flash memory device comprising a reference current source used to provide a reference current for comparison to the current of a memory cell being read, includes an adjustable current source in parallel with the memory cell being read, and an adjustable current source in parallel with the reference current source. The current from the memory cell, reference current source, and their parallel adjustable current sources are input to cascode circuits for conversion to voltages that are compared by a sense amplifier. The behavior of the cascode circuits and sense amplifier in response to changes in the memory cell and reference current source may be evaluated by adjusting the adjustable current sources so that the combined current at each input to the sense amplifier simulates the current of the circuit after aging or cycling.

Abstract: A method of programming and reading a dual cell memory device. The method includes storing a selected program level in each cell and reading one of the cells to determine a single data value stored by the memory device.

Abstract: A method of erasing a sector of flash memory cells wherein a first set of preset pre-erase voltages is applied to the sector of flash memory cells. After the first set of preset pre-erase voltages is applied it is determined if another set of preset pre-erase voltages is to be applied to the sector of flash memory cells. If another set of preset pre-erase voltages is applied and if another set of preset pre-erase set of pre-erase voltages is not to be applied, a standard erase routine is applied to the sector.

Abstract: A method of manufacturing a flash memory semiconductor device that eliminates the step of forming sidewall spacers on n-channel and p-channel transistor gate structures. Resist spacers having a dimension of Gn+2Sn are formed on n-channel transistor gate structures and an N+ implant is performed to form N+ implant is performed to form N+ regions in the n-channel substrate region. Resist spacers having a dimension of Gs +2Sp are formed on p-channel transistor gate structures and a P+ implant is performed to form P+ regions in the p-channel substrate region.

Abstract: A system is provided for reducing band-to-band tunneling current during Flash memory erase operations. The system includes a memory sector divided into (N) I/O subsectors, N being an integer, and a drain pump to generate power for associated erase operations within the N I/O subsectors. An erase sequencing subsystem generates N pulses to enable the erase operations within each of the N I/O subsectors in order to reduce band-to-band tunneling current provided by the drain pump.

Abstract: A method of utilizing Fast Chip Erase to screen endurance rejects. Multiple sectors in a device are selected and a time necessary to program all cells in the sectors is monitored and if the monitored time exceeds a first time, the device fails. A time necessary to erase all the cells without any overerased cells is monitored and if the time exceeds a second time, the device fails. A time necessary to correct overerased cells is monitored and if the time exceeds a third time, the device fails. The total time from erase until overerase correction is achieved is monitored and if the total time exceeds a fourth time, the device fails. The total time to determine erasability is monitored and if this time exceeds a fifth time, the device fails.

Abstract: A method of manufacturing a semiconductor device that eliminates the N+ implant by replacement with resist spacers on n-channel gate structures and a standard Mdd implant. The N+ implant is thereby eliminated from the n-channel transistors and is replaced by an Mdd implant. The Mdd implant is simultaneously implanted into the core transistors and portions of the n-channel transistors unprotected by the resist spacers. The p-channel transistors are then implanted with a PLdd implant, the n-channel transistors are then planted with an NLdd implant, sidewall spacers are formed on all gate structures, the p-channel transistors are implanted with a P+ implant and the N+ and P+ contacts are then formed.

Abstract: An E.sup.2 PROM device includes a semiconductor body having source and drain regions and a channel region, with a gate oxide over the channel region and a floating gate over the gate oxide. An oxide isolation region contains a doped polysilicon erase gate, so that erasing of the device takes place by electron flow from the floating gate to the erase gate through a thin oxide portion of the oxide isolation region, at a position spaced from the gate oxide. The inclusion of the erase gate in the oxide isolation region results in smaller overall device size than previously achieved.

Abstract: A method of testing Flash memory devices by performing wafer sort testing on main array cells and redundancy array cells of the Flash memory device and performing class testing on redundancy array cells only. There is a major savings of testing time with no decrease in quality of the final product.

Abstract: The failure rate of semiconductor devices containing UPROM transistors is improved by erasing the UPROM transistors using X-rays. The semiconductor devices are subsequently exposed to UV radiation to erase other transistors charged during X-ray exposure.