Abstract: A memory system that includes a DRAM cell that includes an access transistor and a storage capacitor. The storage capacitor is fabricated by forming a polysilicon crown electrode, a dielectric layer overlying the polysilicon crown, and a polysilicon plate electrode overlying the dielectric layer. A first set of thermal cycles are performed during the formation of the storage capacitor to form and anneal the elements of the capacitor structure. Subsequently, shall P+ and/or N+ regions are formed by ion implantation, and metal salicide is formed. As a result, the relatively high first set of thermal cycles required to form the capacitor structure does not adversely affect the shallow P+ and N+ regions or the metal salicide. A second set of thermal cycles, which are comparable to or less than the first set of thermal cycles, are performed during the formation of the shallow regions and the metal salicide.

Abstract: A method of operating a system-on-a-chip having a logic circuit and a thin-oxide non-volatile memory embedded or located on a single chip. In this method, the contents of the non-volatile memory cells are read out and stored (with or without data decompression operations) into on-chip or off-chip volatile memory. The data contents of the non-volatile memory cells are then refreshed (through charge injection and removal) with optimum signal condition. The non-volatile memory cells then remain in an idle or standby mode substantially without a significant external electric field, while the system-on-a-chip is operated in response to the data stored in the volatile memory. If a reprogramming operation or a refresh operation is required, then the non-volatile memory cells are reprogrammed or refreshed as required and then returned to the idle or standby mode. As a result, the storage characteristics of the non-volatile memory cells are improved.

Abstract: A system for handling refresh of a DRAM array or other memory array requiring periodic refresh, such that the refresh does not require explicit control signaling between the memory array and a memory controller. External accesses and refresh operations are controlled so that the refresh operations do not interfere with the external accesses under any conditions. A multi-bank refresh scheme is used to reduce the number of collisions between external accesses and refresh operations. A read buffer buffers read data, thereby allowing refresh operations to be performed when consecutive read accesses hit the address range of the same memory bank for a long period of time. A write buffer buffers write data, thereby allowing refresh operations to be performed when consecutive write accesses hit the address range of a single memory bank for a long period of time. Both the read and write buffers can be constructed of DRAM cells.

Abstract: A four-transistor RAM cell is provided by a pair of cross-coupled driver transistors configured to store a data value, and a pair of access transistors coupled to the driver transistors. The driver transistors and access transistors are sized so the driver transistors are not stronger than the access transistors. In one embodiment, the driver transistors are PMOS transistors and the access transistors are NMOS transistors, with these transistors all having substantially the same size. These PMOS and NMOS transistors are fabricated using a conventional ASIC or logic process. The PMOS transistors are located in an N-well, which is biased at a voltage greater than the VCC supply voltage. The gates of the access transistors are coupled to a word line, and the sources of the access transistors are coupled to a pair of bit lines. The bit lines are coupled a regenerative sense amplifier and a bit line equalization circuit.

Abstract: A method and apparatus for handling the refresh of a DRAM array or other memory array requiring periodic refresh operations so that the refresh does not require explicit control signaling nor handshake communication between the memory array and an external accessing client. The method and apparatus handles external accesses and refresh operations such that the refresh operations do not interfere with the external accesses under any conditions. As a result, an SRAM compatible device can be built from DRAM or 1-Transistor cells. A clock division scheme is implemented to allow N external accesses and one refresh operation to be performed during N consecutive clock cycles.

Abstract: A memory system that includes a dynamic random access memory (DRAM) cell including an access transistor and a capacitor structure fabricated in a semiconductor substrate. The capacitor structure is fabricated by forming a cavity in a shallow trench isolation region, thereby exposing a sidewall region of the substrate below the upper surface of the substrate. A dielectric layer is formed over the upper surface and the sidewall region of the substrate. A polysilicon layer is formed over the dielectric layer and patterned to form a capacitor electrode of the capacitor structure that extends over the upper surface and the sidewall region of the substrate. The capacitor electrode is partially recessed below the upper surface of the substrate. The polysilicon layer is also patterned to form the gate electrode of the access transistor.

Abstract: A memory array requiring periodic refresh operations is controlled such that the refresh operations do not require explicit control signaling or handshake communication between the memory array and a memory controller. External accesses and refresh operations are handled such that refresh operations do not interfere with external accesses under any conditions. A multi-bank refresh scheme reduces the number of collisions between refresh operations and external accesses. A read buffer is used to buffer read data, thereby allowing refresh operations to be performed when consecutive read accesses hit the address range of a particular memory bank for a long period of time. A write buffer is used to buffer write data, thereby allowing refresh operations to be performed when consecutive write accesses hit the address range of a particular memory bank for a long period of time. The memory array, read buffer and write buffer can be constructed of DRAM cells.

Abstract: A memory device which utilizes a plurality of memory modules coupled in parallel to a master I/O module through a bus. Each memory module has independent address and command decoders to enable independent operation. Thus each memory module is activated by commands on the bus only when a memory access operation is performed within the particular memory module. Each memory module has a programmable identification register which stores a communication address of the module. The communication address for each module can be changed during operation of the memory device by a command from the bus. The memory device includes redundant memory modules to replace defective memory modules. Replacement can be carried out through commands on the bus.

Abstract: A system for handling refresh of a DRAM array or other memory array requiring periodic refresh, such that the refresh does not require explicit control signaling between the memory array and a memory controller. External accesses and refresh operations are controlled so that the refresh operations do not interfere with the external accesses under any conditions. A multi-bank refresh scheme is used to reduce the number of collisions between external accesses and refresh operations. A read buffer buffers read data, thereby allowing refresh operations to be performed when consecutive read accesses hit the address range of the same memory bank for a long period of time. A write buffer buffers write data, thereby allowing refresh operations to be performed when consecutive write accesses hit the address range of a single memory bank for a long period of time. Both the read and write buffers can be constructed of DRAM cells.

Abstract: A memory system that includes a DRAM cell that includes an access transistor and a storage capacitor. The storage capacitor is fabricated by forming a polysilicon crown electrode, a dielectric layer overlying the polysilicon crown, and a polysilicon plate electrode overlying the dielectric layer. A first set of thermal cycles are performed during the formation of the storage capacitor to form and anneal the elements of the capacitor structure. Subsequently, shallow P+ and/or N+ regions are formed by ion implantation, and metal salicide is formed. As a result, the relatively high first set of thermal cycles required to form the capacitor structure does not adversely affect the shallow P+ and N+ regions or the metal salicide. A second set of thermal cycles, which are comparable to or less than the first set of thermal cycles, are performed during the formation of the shallow regions and the metal salicide.

Abstract: A ternary dynamic CAM cell compatible with a standard logic process includes two ratio-independent 4-transistor (4T) SRAM cells. Each 4T SRAM cell includes a pair of cross-coupled driver transistors for storing data value, and a pair of access transistors. The driver transistors are sized to not be stronger than the access transistors. In one embodiment, the driver and access transistors are PMOS and NMOS, respectively, and are all substantially the same size. A match circuit for each 4T SRAM cell includes a pair of pass transistors serially coupled between a match line and a supply voltage. If the comparand and stored data bits do not match, both pass transistors are turned on, pulling the match line to the supply voltage. “A DON'T CARE” state is created by writing the same logic value to both 4T SRAM cells, so that both match circuits remain off for all input comparands.

Abstract: A method and apparatus for handling the refresh of a DRAM array or other memory array requiring periodic refresh operations so that the refresh does not require explicit control signaling nor handshake communication between the memory array and an external accessing client. The method and apparatus handles external accesses and refresh operations such that the refresh operations do not interfere with the external accesses under any conditions. As a result, an SRAM compatible device can be built from DRAM or 1-Transistor cells. A single-port multi-bank refresh scheme is used to cut down the number of collisions between memory refresh operations and memory data access operations. A read buffer is used to buffer read data, thereby allowing memory refresh operations to be performed when consecutive read accesses hit the address range of a particular memory bank for a long period of time.

Abstract: A semi-conductor memory device having a wide write data bandwidth is provided with high speed read-write circuitry having data amplifiers that are activated to accelerate amplification of write data signals being driven by write data drivers onto data lines of the cell array of the device during memory write cycles, as well as activated to amplify read data signals on the data lines during memory read cycles. Moreover, the data amplifiers are activatedin a self-timed manner. In one embodiment, the device is further provided with a read data buffer that is constituted with a regenerative latch and an input stage, and a write data buffer having multiple entries. The input stage of the read data buffer isolates or couples the regenerative latch to the data lines depending on whether the data lines are in a pre-charged state or not.

Abstract: A non-volatile memory (NVM) system includes a NVM cell having: a semiconductor region having a first conductivity type; a gate dielectric layer located over the semiconductor region; a gate electrode located over the gate dielectric layer; a source region and a drain region of a second conductivity type, opposite the first conductivity type, located in the semiconductor region and aligned with the gate electrode; a crown electrode having a base that contacts the gate electrode and walls that extend vertically from the base region, away from the gate electrode; a dielectric layer located over the crown electrode, wherein the dielectric layer extends over at least interior surfaces of the walls; and a plate electrode located over the dielectric layer, wherein the plate electrode extends over at least interior surfaces of the walls.

Abstract: A memory system that includes a DRAM cell that includes an access transistor and a storage capacitor. The storage capacitor is fabricated by forming a polysilicon crown electrode, a dielectric layer overlying the polysilicon crown, and a polysilicon plate electrode overlying the dielectric layer. A first set of thermal cycles are performed during the formation of the storage capacitor to form and anneal the elements of the capacitor structure. Subsequently, shallow P+ and/or N+ regions are formed by ion implantation, and metal salicide is formed. As a result, the relatively high first set of thermal cycles required to form the capacitor structure does not adversely affect the shallow P+ and N+ regions or the metal salicide. A second set of thermal cycles, which are comparable to or less than the first set of thermal cycles, are performed during the formation of the shallow regions and the metal salicide.

Abstract: A non-volatile memory (NVM) cell is fabricated by slightly modifying a conventional logic process. The NVM cell is fabricated by forming the gate electrode of an access transistor from a first conductive layer, and then forming a capacitor structure that contacts the gate electrode. In one embodiment, the capacitor structure is fabricated by forming a crown electrode of a capacitor structure from a second conductive layer, forming a dielectric layer over the crown electrode, and then forming an plate electrode over the dielectric layer from a third conductive layer. The crown electrode contacts the gate electrode, thereby providing an electrical connection between these electrodes. A first set of thermal cycles are performed during the formation of the capacitor structure. After the capacitor structure has been formed, P+ and/or N+ ion implantations are performed, thereby forming shallow junctions on the chip (e.g., a drain region of the access transistor).

Abstract: A semi-conductor memory device having a wide write data bandwidth is provided with high speed read-write circuitry having data amplifiers that are activated to accelerate amplification of write data signals being driven by write data drivers onto data lines of the cell array of the device during memory write cycles, as well as activated to amplify read data signals on the data lines during memory read cycles. Moreover, the data amplifiers are activated in a self-timed manner. In one embodiment, the device is further provided with a read data buffer that is constituted with a regenerative latch and an input stage, and a write data buffer having multiple entries. The input stage of the read data buffer isolates or couples the regenerative latch to the data lines depending on whether the data lines are in a pre-charged state or not.

Abstract: A method and structure for implementing a DRAM memory array as a second level cache memory in a computer system. The computer system includes a central processing unit (CPU), a first level SRAM cache memory, a CPU bus coupled to the CPU, and a second level cache memory which includes a DRAM array coupled to the CPU bus. When accessing the DRAM array, row access and column decoding operations are performed in a self-timed asynchronous manner. Predetermined sequences of column select operations are then performed in a synchronous manner with respect to a clock signal. A widened data path is provided to the DRAM array, effectively increasing the data rate of the DRAM array. By operating the DRAM array at a higher data rate than the CPU bus, additional time is provided for precharging the DRAM array. As a result, the precharging of the DRAM array is transparent to the CPU bus. A structure and method control the refresh and internal operations of the DRAM array.

Abstract: A method and apparatus for handling the refresh of a DRAM array or other memory array requiring periodic refresh operations so that the refresh does not require explicit control signaling nor handshake communication between the memory array and an external accessing client. The method and apparatus handles external accesses and refresh operations such that the refresh operations do not interfere with the external accesses under any conditions. As a result, an SRAM compatible device can be built from DRAM or 1-Transistor cells. A clock division scheme is implemented to perform external accesses during one portion of a clock cycle, and required refresh operations during another portion of the same clock cycle.

Abstract: A method and structure for implementing a DRAM memory array as a second level cache memory in a computer system. The computer system includes a central processing unit (CPU), a first level SRAM cache memory, a CPU bus coupled to the CPU, and a second level cache memory which includes a DRAM array coupled to the CPU bus. When accessing the DRAM array, row access and column decoding operations are performed in a self-timed asynchronous manner. Predetermined sequences of column select operations are then performed in a synchronous manner with respect to a clock signal. A widened data path is provided to the DRAM array, effectively increasing the data rate of the DRAM array. By operating the DRAM array at a higher data rate than the CPU bus, additional time is provided for precharging the DRAM array. As a result, the precharging of the DRAM array is transparent to the CPU bus. A structure and method control the refresh and internal operations of the DRAM array.