Abstract: Balanced electrical performance in a static random access memory (SRAM) cell with an asymmetric context such as a buffer circuit. Each memory cell includes a circuit feature, such as a read buffer, that has larger transistor sizes and features than the other transistors within the cell, and in which the feature asymmetrical influences the smaller cell transistors. For best performance, pairs of cell transistors are to be electrically matched with one another. One or more of the cell transistors nearer to the asymmetric feature are constructed differently, for example with different channel width, channel length, or net channel dopant concentration, to compensate for the proximity effects of the asymmetric feature.

Abstract: Balanced electrical performance in a static random access memory (SRAM) cell with an asymmetric context such as a buffer circuit. Each memory cell includes a circuit feature, such as a read buffer, that has larger transistor sizes and features than the other transistors within the cell, and in which the feature asymmetrical influences the smaller cell transistors. For best performance, pairs of cell transistors are to be electrically matched with one another. One or more of the cell transistors nearer to the asymmetric feature are constructed differently, for example with different channel width, channel length, or net channel dopant concentration, to compensate for the proximity effects of the asymmetric feature.

Abstract: A static random-access memory (SRAM) in an integrated circuit with circuitry for timing the enabling of sense amplifiers. The memory includes read/write SRAM cells, along with word-line tracking transistors arranged in one or more rows along a side of the read/write cells, and read-tracking transistors arranged in a column along a side of the read/write cells. A reference word line extends over the word-line tracking transistors, with its far end from the driver connected to pass transistors in the read-tracking transistors. The read-tracking transistors are preset to a known data state that, when accessed responsive to the reference word line, discharges a reference bit line, which in turn drives a sense amplifier enable signal.

Abstract: An SRAM with buffered-read bit cells is disclosed (FIGS. 1-6). The integrated circuit includes a plurality of memory cells (102). Each memory cell has a plurality of transistors (200, 202). A first memory cell (FIG. 2) is arranged to store a data signal in response to an active write word line (WWL) and to produce the data signal in response to an active read word line (RWL). A test circuit (104) formed on the integrated circuit is operable to test current and voltage characteristics of each transistor of the plurality of transistors of the first memory cell (FIGS. 7-10).

Abstract: An integrated circuit containing an SAR SRAM and CMOS logic, in which sidewall spacers on the gate extension of the SAR SRAM cell are thinner than sidewall spacers on the logic PMOS gates, so that the depth of the drain node SRAM PSD layer is maintained under the stretch contact. A process of forming an integrated circuit containing an SAR SRAM and CMOS logic, including selectively etch the sidewall spacers on the on the gate extension of the SAR SRAM cell, so that the depth of the drain node SRAM PSD layer is maintained under the stretch contact. A process of forming an integrated circuit containing an SAR SRAM and CMOS logic, including selectively implanting extra p-type dopants in the drain node SRAM PSD layer, so that the depth of the drain node SRAM PSD layer is maintained under the stretch contact.

Abstract: An integrated circuit including a complementary metal-oxide-semiconductor (CMOS) static random access memory (SRAM) with periodic deep well structures within the memory cell array. The deep well structures are contacted by surface well regions of the same conductivity type (e.g., n-type) in the memory cell array, forming two-dimensional grids of both n-type and p-type semiconductor material in the memory cell array area. Bias conductors may contact the grids to apply the desired well bias voltages, for example in well-tie regions or peripheral circuitry adjacent to the memory cell array.

Abstract: Solid-state random access memory including error correction capability applied to memory arrays entering and exiting a data retention mode. Error correction coding of the data to be retained is performed upon determining that a portion of the memory is to enter data retention mode; the parity bits (i.e., bits in addition to those required for storage of the payload) are stored in available memory cells within or external to the retention domain. Upon exit from retention mode, the code words are decoded to correct any errors, and the payload data are returned to the original cells. Error correction encoding and decoding is not performed in the normal operating mode.

Abstract: An embodiment of the invention provides a method of repairing soft failures in memory cells of an SRAM array. The SRAM array is tested to determine the location and type of soft failures in the memory cells. An assist circuit is activated that changes a voltage in a group of memory cells with the same type of soft failure. The change in voltage created by the assist circuit repairs the soft failures in the group. The group may be a word line or a bit line. The type of soft failures includes a failure during a read of a memory cell and a failure during the write of a memory cell.

Abstract: A method of screening static random access memory (SRAM) arrays to identify memory cells with bit line side pass transistor defects. After writing a known data state to the memory cells under test, a forward back-bias is applied to the load transistors of those cells. A write of the opposite data state is then performed, followed by a read of the memory cells. The process is repeated for the opposite data state.

Abstract: Balanced electrical performance in a static random access memory (SRAM) cell with an asymmetric context such as a buffer circuit. Each memory cell includes a circuit feature, such as a read buffer, that has larger transistor sizes and features than the other transistors within the cell, and in which the feature asymmetrical influences the smaller cell transistors. For best performance, pairs of cell transistors are to be electrically matched with one another. One or more of the cell transistors nearer to the asymmetric feature are constructed differently, for example with different channel width, channel length, or net channel dopant concentration, to compensate for the proximity effects of the asymmetric feature.

Abstract: An integrated circuit and method of generating a layout for an integrated circuit in which circuitry peripheral to an array of repetitive features, such as memory or logic cells, is realized according to devices constructed similarly as the cells themselves, in one or more structural levels. The distance over which proximity effects are caused in various levels is determined. Those proximity effect distances determine the number of those features to be repeated outside of and adjacent to the array for each level, within which the peripheral circuitry is constructed to match the construction of the repetitive features in the array.

Abstract: An integrated circuit and method of generating a layout for an integrated circuit in which circuitry peripheral to an array of repetitive features, such as memory or logic cells, is realized according to devices constructed similarly as the cells themselves, in one or more structural levels. The distance over which proximity effects are caused in various levels is determined. Those proximity effect distances determine the number of those features to be repeated outside of and adjacent to the array for each level, within which the peripheral circuitry is constructed to match the construction of the repetitive features in the array.

Abstract: A solid-state memory in which each memory cell is constructed of complementary metal-oxide-semiconductor (CMOS) inverters implemented with dual stress liner (DSL) technology. Asymmetry is incorporated into each memory cell by constructing one of the inverter transistors or the pass-gate transistor using the stress liner with opposite stress characteristics from its opposing counterpart. For example, both of the p-channel load transistors and one of the n-channel driver transistors in each memory cell may be constructed with a compressive nitride liner layer while the other driver transistor is constructed with a tensile nitride liner layer. In another implementation, one of the n-channel pass-gate transistors is constructed with a compressive nitride liner layer while the other pass-gate transistor is constructed with a tensile nitride liner layer. Improved cell stability due to the resulting asymmetric behavior is implemented in a cost-free manner.

Abstract: A screening method for testing solid-state memories for the effects of long-term shift and random telegraph noise (RTN). In the context of static random access memories (SRAMs), each memory cell in the array is functionally tested with a bias voltage (e.g., the cell power supply voltage) at a severe first guardband sufficient to account for worst case long-term shift and RTN effects. Cells failing the first guardband are then repeatedly tested with the bias voltage at a second guardband, less severe than the first guardband; if the tested cells pass this second guardband, the suspect cells are considered to not be vulnerable to RTN effects. Over-screening due to an unduly severe guardband is avoided, while still screening vulnerable memories from the population.

Abstract: A method of programming a memory array having plural subarrays is disclosed. (FIG. 3). The method comprises determining a minimum operating voltage (Vmin) for each subarray of the plural subarrays (306). A first voltage is applied to each subarray having a minimum operating voltage greater than a predetermined voltage (420, 422, 424). A second voltage is applied to each subarray having a minimum operating voltage less than the predetermined voltage (308 and 426, 428).

Abstract: A method of screening complementary metal-oxide-semiconductor CMOS integrated circuits, such as integrated circuits including CMOS static random access memory (SRAM) cells, for n-channel transistors susceptible to transistor characteristic shifts over operating time. For the example of SRAM cells formed of cross-coupled CMOS inverters, static noise margin and writeability (Vtrip) screens are provided. Each of the n-channel transistors in the CMOS SRAM cells are formed within p-wells that are isolated from p-type semiconductor material in peripheral circuitry of the memory and other functions in the integrated circuit. Forward and reverse body node bias voltages are applied to the isolated p-wells of the SRAM cells under test to determine whether such operations as read disturb, or write cycles, disrupt the cells under such bias. Cells that are vulnerable to threshold voltage shift over time can thus be identified.

Abstract: A method of screening static random access memory (SRAM) arrays to identify memory cells with bit line side pass transistor defects. After writing a known data state to the memory cells under test, a forward back-bias is applied to the load transistors of those cells. A write of the opposite data state is then performed, followed by a read of the memory cells. The process is repeated for the opposite data state.

Abstract: Integrated circuit for performing test operation of static RAM bit and for measuring the read margin, write margin, and stability margin of SRAM bits with operational circuitry that includes effects of the SRAM array architecture and circuit design. In addition, the integrated circuit has a built-in self-test circuit for measuring the read margin, write margin, and stability margin of SRAM that excludes the effects of SRAM array architecture and circuit design.

Abstract: A screening method for testing solid-state memories for the effects of long-term shift and random telegraph noise (RTN). In the context of static random access memories (SRAMs), each memory cell in the array is functionally tested with a bias voltage (e.g., the cell power supply voltage) at a severe first guardband sufficient to account for worst case long-term shift and RTN effects. Cells failing the first guardband are then repeatedly tested with the bias voltage at a second guardband, less severe than the first guardband; if the tested cells pass this second guardband, the suspect cells are considered to not be vulnerable to RTN effects. Over-screening due to an unduly severe guardband is avoided, while still screening vulnerable memories from the population.

Abstract: A method of screening complementary metal-oxide-semiconductor CMOS integrated circuits, such as integrated circuits including CMOS static random access memory (SRAM) cells, for transistors susceptible to transistor characteristic shifts over operating time. For the example of SRAM cells formed of cross-coupled CMOS inverters, separate ground voltage levels can be applied to the source nodes of the driver transistors, or separate power supply voltage levels can be applied to the source nodes of the load transistors (or both). Asymmetric bias voltages applied to the transistors in this manner will reduce the transistor drive current, and can thus mimic the effects of bias temperature instability (BTI). Cells that are vulnerable to threshold voltage shift over time can thus be identified.