摘要:
An improved contactless EPROM array, EPROM cell design, and method for fabricating the same is based on a unique drain-source-drain configuration, in which a single source diffusion is shared by two columns of transistors. An elongated first drain diffusion region, an elongated source diffusion region, and an elongated second drain diffusion region, are formed in a semi-conductor substrate along essentially parallel lines. Field oxide regions are grown on opposite sides of the first and second drain diffusion regions. Floating gates and control gate wordlines are formed orthogonal to the drain-source-drain structure to establish two columns of storage cells having a shared source region. The shared source region is coupled through a bottom block select transistor to a virtual ground terminal. Each drain diffusion region is-coupled through a top block select transistor to global bitline. The cell structure uses two metal global bitlines which extend essentially parallel to the drain, source and drain diffusion regions, and a virtual ground conductor which couples a plurality of columns of transistors to a virtual ground terminal through a horizontal conductor, such as a buried diffusion line.
摘要:
An improved contactless EPROM array, EPROM cell design, and method for fabricating the same is based on a unique drain-source-drain configuration, in which a single source diffusion is shared by two columns of transistors. An elongated first drain diffusion region, an elongated source diffusion region, and an elongated second drain diffusion region, are formed in a semi-conductor substrate along essentially parallel lines. Field oxide regions are grown on opposite sides of the first and second drain diffusion regions. Floating gates and control gate wordlines are formed orthogonal to the drain-source-drain structure to establish two columns of storage cells having a shared source region. The shared source region is coupled through a bottom block select transistor to a virtual ground terminal. Each drain diffusion region is coupled through a top block select transistor to global bitline. The cell structure uses two metal global bitlines which extend essentially parallel to the drain, source and drain diffusion regions, and a virtual ground conductor which couples a plurality of columns of transistors to a virtual ground terminal through a horizontal conductor, such as a buried diffusion line.
摘要:
A circuit for speeding up the pre-programming of floating gate storage transistors such as FLASH EPROMS, and particularly speeding up the pre-programming of a block or array of floating gate storage transistors includes a controllable voltage source that supplies gate programming potential across the control gate and source of the FLASH EPROM transistor cells to be programmed. A control circuit is provided that controls the voltage source to vary the gate programming potential during a programming interval as a function of time in order to decrease the time required for a given amount of charge movement to program the selected floating gate transistors. The wordline voltages are varied, while the source voltage is held constant. By starting at a lower wordline voltage, and increasing during the programming interval to a high wordline voltage, the programming speed is increased, and the high final turn-on threshold voltage for the programmed floating gate storage transistors is achieved. In addition, in order to speed up pre-programming, a programming potential is applied to four wordlines in parallel during a single programming interval. Further, the load on cells being programmed is adjusted to improve programming speed.
摘要:
A circuit for speeding up the pre-programming of floating gate storage transistors such as FLASH EPROMS, and particularly speeding up the pre-programming of a block or array of floating gate storage transistors includes a controllable voltage source that supplies gate programming potential across the control gate and source of the FLASH EPROM transistor cells to be programmed. A control circuit is provided that controls the voltage source to vary the gate programming potential during a programming interval as a function of time in order to decrease the time required for a given amount of charge movement to program the selected floating gate transistors. The wordline voltages are varied, while the source voltage is held constant. By starting at a lower wordline voltage, and increasing during the programming interval to a high wordline voltage, the programming speed is increased, and the high final turn-on threshold voltage for the programmed floating gate storage transistors is achieved. In addition, in order to speed up pre-programming, a programming potential is applied to four wordlines in parallel during a single programming interval. Further, the load on cells being programmed is adjusted to improve programming speed.
摘要:
An improved contactless EPROM array, EPROM cell design, and method for fabricating the same is based on a unique drain-source-drain configuration, in which a single source diffusion is shared by two columns of transistors. An elongated first drain diffusion region, an elongated source diffusion region, and an elongated second drain diffusion region, are formed in a semi-conductor substrate along essentially parallel lines. Field oxide regions are grown on opposite sides of the first and second drain diffusion regions. Floating gates and control gate wordlines are formed orthogonal to the drain-source-drain structure to establish two columns of storage cells having a shared source region. The shared source region is coupled through a bottom block select transistor to a virtual ground terminal. Each drain diffusion region is coupled through a top block select transistor to global bitline. The cell structure uses two metal global bitlines which extend essentially parallel to the drain, source and drain diffusion regions, and a virtual ground conductor which couples a plurality of columns of transistors to a virtual ground terminal through a horizontal conductor, such as a buried diffusion line.
摘要:
Novel contactless FLASH EPROM cell and array designs, and methods for fabricating the same is based on a unique drain-source-drain configuration, in which a single source diffusion is shared by two columns of transistors. An elongated first drain diffusion region, an elongated source diffusion region, and an elongated second drain diffusion region, are formed in a semi-conductor substrate along essentially parallel lines. Field oxide regions are grown on opposite sides of the first and second drain diffusion regions. Floating gates and control gate wordlines are formed orthogonal to the drain-source-drain structure to establish two columns of storage cells having a shared source region. The shared source region is coupled through a bottom block select transistor to a virtual ground terminal. Each drain diffusion region is coupled through a top block select transistor to global bitline. The cell structure uses two metal global bitlines which extend essentially parallel to the drain, source and drain diffusion regions, and a virtual ground conductor which couples a plurality of columns of transistors to a virtual ground terminal through a horizontal conductor, such as a buried diffusion line.
摘要:
A floating gate memory with a protocol which terminates a program load cycle upon detecting a predetermined address and/or data pattern, providing positive indication of the end of the load cycle, and eliminating the requirement for a long pulse in a controlled signal. Command logic executes a process to store a block of data in response to a sequence of addresses and data segments received at the input/output circuitry, and detects the last segment in a block of data in response to a pattern including at least one of the addresses and data segments received at the input/output circuitry. One pattern includes consecutive matching addresses. Pattern match logic included in the command logic is coupled to the input/output circuitry and stores addresses in the sequence and compares them with a next address to indicate a matching address. Alternatively, the pattern includes both matching addresses and data segments with corresponding comparator circuitry. Alternatively, the pattern comprises a command address which is outside the address field of the memory array. The command address may include all or only a high order segment of the actual data address. The floating gate memory includes a state machine which automatically programs and verifies programming of the block of data after the last segment of the block is detected, and may comprise a flash memory or electrically erasable programmable read only memory (EEPROM).
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:
A circuit for speeding up the pre-programming of floating gate storage transistors such as FLASH EPROMS, and particularly speeding up the pre-programming of a block or array of floating gate storage transistors includes a controllable voltage source that supplies gate programming potential across the control gate and source of the FLASH EPROM transistor cells to be programmed. A control circuit is provided that controls the voltage source to vary the gate programming potential during a programming interval as a function of time in order to decrease the time required for a given amount of charge movement to program the selected floating gate transistors. The wordline voltages are varied, while the source voltage is held constant. By starting at a lower wordline voltage, and increasing during the programming interval to a high wordline voltage, the programming speed is increased, and the high final turn-on threshold voltage for the programmed floating gate storage transistors is achieved. In addition, in order to speed up pre-programming, a programming potential is applied to four wordlines in parallel during a single programming interval. Further, the load on cells being programmed is adjusted to improve programming speed.
摘要:
A circuit for speeding up the pre-programming of floating gate storage transistors such as FLASH EPROMS, and particularly speeding up the pre-programming of a block or array of floating gate storage transistors includes a controllable voltage source that supplies gate programming potential across the control gate and source of the FLASH EPROM transistor cells to be programmed. A control circuit is provided that controls the voltage source to vary the gate programming potential during a programming interval as a function of time in order to decrease the time required for a given amount of charge movement to program the selected floating gate transistors. The wordline voltages are varied, while the source voltage is held constant. By starting at a lower wordline voltage, and increasing during the programming interval to a high wordline voltage, the programming speed is increased, and the high final turn-on threshold voltage for the programmed floating gate storage transistors is achieved. In addition, in order to speed up pre-programming, a programming potential is applied to four wordlines in parallel during a single programming interval. Further, the load on cells being programmed is adjusted to improve programming speed.