摘要:
A method and apparatus are provided for high performance, high voltage memory operations on selected memory cells (200) of a semiconductor memory device (100). A high voltage generator (106) during program or erase operations provides a continuous high voltage level (702) on selected word lines (502) and maintains a continuous high voltage level supply to a bit line decoder (120) which sequentially provides the high voltage level (706) to a first portion of bit lines (504) and discharges (708) those bit lines (504) before providing the high voltage level to a second portion (710). For additional improvements to program operations, the high voltage generator (106) decouples high voltages provided to the word lines (502) and the bit lines (504) by providing a current flow control device (1208) therebetween and provides a boosting voltage at a time (1104) to overcome a voltage level drop (1102) resulting from a capacitor load associated with selected bit lines (504) and/or the bit line decoder (120) precharges (1716) a second portion of the bit lines (504) while providing a high voltage level to a first portion to program (1706) a first portion of memory cells (200). For improvements to read operations, whether dynamic reference cells (2002) are blank is determined by providing non-identically regulated high voltage levels from a first voltage source (2112) to the dynamic reference cells (2002) and from a second voltage source (2104) to static reference cells (2004) and, if the dynamic reference cells (2002) are not blank, reads selected memory cells (200) by providing identically regulated high voltage levels to the selected memory cells (200), the dynamic reference cells (2002) and the static reference cells (2004).
摘要:
Systems and methodologies are provided herein for increasing operation speed uniformity in a flash memory device. Due to the characteristics of a typical flash memory array, memory cells in a memory array may experience distributed substrate resistance that increases as the distance of the memory cell from an edge of the memory array increases. This difference in distributed substrate resistance can vary voltages supplied to different memory cells in the memory array depending on their location, which can in turn cause non-uniformity in the speed of high voltage operations on the memory array such as programming. The systems and methodologies provided herein reduce this non-uniformity in operation speed by providing compensated voltage levels to memory cells in a memory array based at least in part on the location of each respective memory cell. For example, a compensated operation voltage can be provided that is higher near the center of the memory array and lower near an edge of the memory array, thereby lessening the effect of distributed substrate resistance and providing increased operation speed uniformity throughout the memory array.
摘要:
Systems and/or methods that facilitate discharging bit lines (BL) associated with memory arrays in nonvolatile memory at a controlled rate are presented. A discharge component facilitates discharging the BL at a desired rate thus preventing the “hot switching” phenomenon from occurring within a y-decoder component(s) associated with the nonvolatile memory. The discharge component can be comprised of, in part, a discharge transistor component that controls the rate of BL discharge wherein the gate voltage of the discharge transistor component can be controlled by a discharge controller component. The rate of BL discharge can be determined by the size of discharge transistor component used in the design, the strength and/or size of the y-decoder component, the number of erase errors that occur for a particular memory device, and/or other factors in order to facilitate preventing hot switching from occurring.
摘要:
Systems and methodologies are provided herein for increasing operation speed uniformity in a flash memory device. Due to the characteristics of a typical flash memory array, memory cells in a memory array may experience distributed substrate resistance that increases as the distance of the memory cell from an edge of the memory array increases. This difference in distributed substrate resistance can vary voltages supplied to different memory cells in the memory array depending on their location, which can in turn cause non-uniformity in the speed of high voltage operations on the memory array such as programming. The systems and methodologies provided herein reduce this non-uniformity in operation speed by providing compensated voltage levels to memory cells in a memory array based at least in part on the location of each respective memory cell. For example, a compensated operation voltage can be provided that is higher near the center of the memory array and lower near an edge of the memory array, thereby lessening the effect of distributed substrate resistance and providing increased operation speed uniformity throughout the memory array.
摘要:
A semiconductor memory device (104) selectably connectable to an external high voltage power supply (122) is provided. The semiconductor memory device (104) includes a switch (314), a detector (316) and a timing device (318). The switch (314) is connected to external voltage supply signals and selectably couples the external voltage supply signals to memory cells (305) of the semiconductor memory device (104) for memory operations thereof. The external voltage supply signals including a high voltage signal (412) provided from the external high voltage power supply (122) and an operational voltage signal Vcc (402). The detector (316) is connected to the external voltage supply signals for generating a timer activation signal (404) in response to detecting an operational voltage power-on period. The timing device (318) signals the switch (314) to decouple the high voltage signal (412) and the operational voltage signal (402) from the memory cells (305) in response to the timer activation signal (404) and to recouple the high voltage signal (412) and the operational voltage signal (402) to the memory cells (305) a time delay interval thereafter. The time delay interval is determined in response to the high voltage signal (412).
摘要:
One embodiment of the invention relates to a method for accessing a memory cell. In this method, at least one bit of the memory cell is erased. After erasing the at least one bit, a soft program operation is performed to bias the memory cell thereby improving the reliability of data stored in the memory cell.Other methods and systems are also disclosed.
摘要:
A voltage regulator may include an operational-amplifier section, a capacitor connected to an output of the operational-amplifier section, and a switch configured to connect the capacitor to a voltage supply. The switch is configured to charge the capacitor before activating the operational-amplifier section. The capacitor is configured to store charge to supplement current being supplied from the operational-amplifier section. The voltage regulator may be used to supply power to non-volatile memory cells.
摘要:
A method and apparatus are provided for improved power conservation in a semiconductor device (100) which includes a high voltage generating circuit (200) such as a drain pump. The operation frequency of the drain pump (200) is controlled in response to the high voltage level detected at the output thereof. In addition, highly efficient operation of the drain pump (200) can be achieved by enabling and disabling the drain pump (200) in response to the high voltage level to provide an output signal at a relatively constant high voltage level. The drain pump (200) is enabled in response to a high voltage detector (202, 402, 502) detecting a high voltage level lower than a first predetermined voltage level and is disabled in response to detecting a voltage level higher than a second predetermined voltage level, the second predetermined voltage level being higher than the first predetermined voltage level.
摘要:
A method of generating an operating condition projection corresponding to a predetermined lifetime for semiconductor devices is disclosed. The disclosed method includes collecting lifetime information from a plurality of semiconductor devices at more than one stress condition by inducing a predetermined drain-source voltage for each stress condition. The method also includes determining the median lifetime for semiconductor devices at each of the stress conditions. Further, the method includes calculating a lifetime at each stress condition at which a predetermined percentage of the devices will exceed and extrapolating the lifetime for devices used at operating conditions.
摘要:
A method of semiconductor integrated circuit fabrication. Specifically, one embodiment of the present invention discloses a method for reducing shallow trench isolation (STI) corner recess of silicon in order to reduce STI edge thinning for peripheral thin gate transistor devices 480 in an integrated circuit 400 comprising flash memory devices 380, and both thick 390 and thin 480 gate transistor devices. The method begins by forming a tunnel oxide layer 310 over a semiconductor substrate 430 for the formation of the flash memory devices 380 (step 220). A mask 350 is formed over the thin gate transistor devices 480 to inhibit formation of a thick gate oxide layer 360 for the formation of the thick gate transistor devices 390 (step 230). The mask 350 reduces shallow trench isolation (STI) recess by eliminating removal of the thick gate oxide layer 360 before forming a thin oxide layer 410 for the thin gate transistor devices 480.