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: 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. Each memory cell includes a pair of cross-coupled CMOS inverters, and corresponding pass gates for coupling the cross-coupled storage nodes to first and second bit lines. 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.

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 parametric test circuit is disclosed (FIG. 6). The test circuit includes a latch circuit having true and complementary terminals. A first access transistor (206) has a current path connected between the true terminal and a first access terminal (214) and has a first control terminal. A second access transistor (208) has a current path connected between the complementary terminal and a second access terminal (216) and has a second control terminal connected to the first control terminal. A first pass gate (604) has a current path connected between the first access terminal (214) and a third access terminal (XBLT) and has a third control terminal. A second pass gate (606) has a current path connected between the second access terminal (216) and a fourth access terminal (XBLB) and has a fourth control terminal connected to the third control terminal.

Abstract: A static random access memory (SRAM) and method of evaluating the same for cell stability, write margin, and read current margin. The memory is constructed so that bit line precharge can be disabled, and so that complementary bit lines for each column of cells can float during memory operations. The various tests are performed by precharging the bit lines for a column, then floating the bit lines, and while the bit lines are floating, pulsing the word lines of one or more selected cells to cause the voltage on one of the bit lines to discharge. The discharged bit line voltage is then applied to another cell, which is then read in a normal read operation to determine whether its state changed due to the discharged bit line voltage. The memory can be characterized for cell stability, write margin, and read current margin in this manner; the method can also be adapted into a manufacturing margin screen, or used in failure analysis.

Abstract: A parametric test circuit is disclosed (FIG. 8B). The test circuit includes a latch circuit having true and complementary terminals. A first access transistor (206) has a current path connected between the true terminal and a first access terminal (214) and has a first control terminal. A second access transistor (208) has a current path connected between the complementary terminal and a second access terminal (216) and has a second control terminal connected to the first control terminal. A multiplex circuit (804) is arranged to apply a first voltage (VDD1) to the first power supply terminal in response to a first state of a select signal (SEL) and to apply a second voltage (VDD2) to the first power supply terminal in response to a second state of a select signal.

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 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: Methods 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, methods for measuring the read margin, write margin, and stability margin of SRAM that excludes the effects of SRAM array architecture and circuit design.

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: A static random access memory (SRAM) and method of evaluating the same for cell stability, write margin, and read current margin. The memory is constructed so that bit line precharge can be disabled, and so that complementary bit lines for each column of cells can float during memory operations. The various tests are performed by precharging the bit lines for a column, then floating the bit lines, and while the bit lines are floating, pulsing the word lines of one or more selected cells to cause the voltage on one of the bit lines to discharge. The discharged bit line voltage is then applied to another cell, which is then read in a normal read operation to determine whether its state changed due to the discharged bit line voltage. The memory can be characterized for cell stability, write margin, and read current margin in this manner; the method can also be adapted into a manufacturing margin screen, or used in failure analysis.

Abstract: Methods 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, methods 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 test method includes providing an integrated circuit, where the integrated circuit includes a memory base cell, where the memory base cell includes a first storage node set, a second storage node set, a set of other nodes, and a set of circuit elements each having a plurality of terminals, where the set of other nodes includes a first data node for accessing the first storage node set, a first access control node for controlling the access of the first storage node set, a first supply node for supplying the first storage node set, and a second supply node for supplying the second storage node set, where the first and second supply nodes are of the same sinking or sourcing type.

Abstract: A test method includes providing an integrated circuit, where the integrated circuit includes a memory base cell, where the memory base cell includes a first storage node set, a second storage node set, a set of other nodes, and a set of circuit elements each having a plurality of terminals, where the set of other nodes includes a first data node for accessing the first storage node set, a first access control node for controlling the access of the first storage node set, a first supply node for supplying the first storage node set, and a second supply node for supplying the second storage node set, where the first and second supply nodes are of the same sinking or sourcing type.

Abstract: A parametric test circuit is disclosed (FIG. 6). The test circuit includes a latch circuit having true and complementary terminals. A first access transistor (206) has a current path connected between the true terminal and a first access terminal (214) and has a first control terminal. A second access transistor (208) has a current path connected between the complementary terminal and a second access terminal (216) and has a second control terminal connected to the first control terminal. A first pass gate (604) has a current path connected between the first access terminal (214) and a third access terminal (XBLT) and has a third control terminal. A second pass gate (606) has a current path connected between the second access terminal (216) and a fourth access terminal (XBLB) and has a fourth control terminal connected to the third control terminal.

Abstract: A parametric test circuit is disclosed (FIG. 8B). The test circuit includes a latch circuit having true and complementary terminals. A first access transistor (206) has a current path connected between the true terminal and a first access terminal (214) and has a first control terminal. A second access transistor (208) has a current path connected between the complementary terminal and a second access terminal (216) and has a second control terminal connected to the first control terminal. A multiplex circuit (804) is arranged to apply a first voltage (VDD1) to the first power supply terminal in response to a first state of a select signal (SEL) and to apply a second voltage (VDD2) to the first power supply terminal in response to a second state of a select signal.

Abstract: A method of preparing Shmoo plots where both the number of failures and also the failure type is specified at each test voltage measurement point. A method that uses the operational SRAM array circuitry to determine the type of failure that may have occurred at each test voltage measurement point.

Abstract: A method of preparing Shmoo plots where both the number of failures and also the failure type is specified at each test voltage measurement point. A method that uses the operational SRAM array circuitry to determine the type of failure that may have occurred at each test voltage measurement point.

Abstract: Methods 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, methods for measuring the read margin, write margin, and stability margin of SRAM that excludes the effects of SRAM array architecture and circuit design.

Abstract: An integrated circuit containing a memory and a sense amplifier. The integrated circuit also containing an extended delay circuit which extends the delay between when a precharged bitline is floated and when a wordline is enabled. A method of testing an integrated circuit to identify bitlines with excessive leakage.