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 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 fault-tolerant, high-speed wafer scale system includes a plurality of functional memory modules, each having associated sense amplifiers which act as high-speed cache memory, a parallel hierarchical bus which is fault-tolerant to defects and a interconnect network, and one or more bus masters. By grouping the DRAM arrays into logically independent modules of relatively small memory capacity (588 Kbit), a large number of cache lines (128) is obtained at small main memory capacity (4 Megabytes). The large number of cache lines allows maintaining a high cache hit rate (greater than 90%).

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 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 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 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 fault-tolerant, high-speed wafer scale system comprises a plurality of functional modules, a parallel hierarchical bus which is fault-tolerant to defects in an interconnect network, and one or more bus masters. This bus includes a plurality of bus lines segmented into sections and linked together by programmable bus switches and bus transceivers or repeaters in an interconnect network.

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 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 memory device which utilizes a plurality of memory modules coupled in parallel to a master I/O module through a single directional asymmetrical signal swing (DASS) bus. This structure provides an I/O scheme having symmetrical swing around half the supply voltage, high through-put, high data bandwidth, short access time, low latency and high noise immunity. The device utilizes improved column access circuitry including an improved address sequencing circuit and a data amplifier within each memory module. A resynchronization circuit allows the device to operate either synchronously and asynchronously using the same pins. Each memory module has independent address and command decoders to enable independent operation so that each memory module is activated by commands on the DASS bus only when a memory access operation is performed within the particular memory module. Redundant memory modules are included to replace defective memory modules, and replacement can be carried out through commands on the DASS bus.

Abstract: A memory system that includes a dynamic random access memory (DRAM) cell, a word line, and a CMOS word line driver fabricated using a conventional logic process. The word line driver is controlled to provide a positive boosted voltage and a negative boosted voltage to the word line, thereby controlling access to the DRAM cell. A positive boosted voltage generator is provided to generate the positive boosted voltage, such that this voltage is greater than V.sub.dd but less than V.sub.dd plus the absolute value of a transistor threshold voltage V.sub.t. Similarly, a negative boosted voltage generator is provided to generate a negative boosted voltage, such that this voltage is less than V.sub.SS by an amount less than V.sub.t. A coupling circuit is provided between the word line driver and one of the positive or negative boosted voltage generators. The coupling circuit couples the word line driver to the selected one of the positive or negative boosted word line generators only when the word line is activated.

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 structure which stores charge useful in a DRAM provides small cell size and eliminates subthreshold leakage current of the access transistor in the cell. Hence this is highly suitable for use for instance in ASICs (applications specific integrated circuits) which are fabricated using "logic" circuit fabrication techniques which normally do not accommodate DRAM cells. The DRAM charge storage structure includes a p-channel access transistor and an n-doped well in a p-doped substrate, a p-channel charge storage capacitor with its source/drain directly connected to the source region of the access field effect transistor, a source of a voltage to the gate of the storage capacitor, and a voltage source connected to the wordline and thereby to the gate terminal of the access transistor which switches between two voltage levels.

Abstract: A method and apparatus for handling the refresh of a DRAM array or other memory array that requires periodic refresh operations. 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. The apparatus includes a multi-bank DRAM memory and an SRAM cache that stores the most recently accessed data. Each of the DRAM banks is operated with independent control, thereby enabling parallel refresh operations and read-write accesses to different banks. The capacity of the SRAM cache is selected such that refresh operations can be carried out even under the condition of indefinite 100% access of the multi-bank DRAM memory.

Abstract: A method and structure for performing a screen refresh operation in a video processing system which includes a frame buffer memory and a display controller coupled to a system bus. A status bit memory is used to store status bits which represent the repetitive characteristics of pixel data stored in the frame buffer memory. The status bits are provided to the display controller. In response, the display controller determines whether to provide pixel data by regenerating pixel data previously retrieved from the frame buffer memory or by accessing the frame buffer memory.

Abstract: A multi-port DRAM cell structure that enables read, write and refresh accesses at each port of the DRAM cell. The DRAM cell includes a storage capacitor for storing a data value, and a plurality of ports for accessing the storage capacitor. Each port enables both read and write accesses to the storage capacitor. Each port can include a port access transistor, a port bitline and a port wordline. The port access transistor includes a gate electrode, a source and a drain. The source of the port access transistor is coupled to the storage capacitor, the drain of the port access transistor is coupled to the port bitline, and the gate electrode of the port access transistor is coupled to the port wordline. This cell architecture enables overlapping read and write accesses to be simultaneously performed at the various ports of the multi-port DRAM cell.