Patent application number | Description | Published |
20090173971 | MEMORY CELL LAYOUT STRUCTURE WITH OUTER BITLINE - An integrated circuit (IC) includes a memory cell having source/drain regions for defining source/drains of a first pull-up or pull-down (PU/PD) transistor for a first storage node, a second PU/PD transistor for a second storage node, and driver, cell pass, and buffer pass transistors. The memory cell includes a first gate electrode region for the first PU/PD and driver transistors, a second gate electrode region for the cell pass and buffer pass transistors, and a third gate electrode region for the second PU/PD transistor. The third gate electrode region and the cell pass transistor are coupled to the first storage node and the first gate electrode region is coupled to the second storage node. The buffer pass and driver transistors are coupled to a source/drain path of the cell pass transistor and the buffer pass transistor is coupled between a bitline (BL) node and the driver transistor. | 07-09-2009 |
20090175113 | CHARACTERIZATION OF BITS IN A FUNCTIONAL MEMORY - Embodiments of the present disclosure provide an integrated circuit including a functional memory and methods of characterizing a component or a defect of a memory cell in the functional memory. In one embodiment, the functional memory includes row and column periphery units having periphery sourcing and sinking voltage supply ports, an array of memory cells organized in rows and columns and a word line controlled by a word line driver that provides row access to a memory cell of the array. Additionally, the functional memory also includes a bit line controlled by a direct bit line access circuit that provides direct bit line access to the memory cell through a bit line analog access port and an independent voltage supply port. | 07-09-2009 |
20100110807 | Bitline Leakage Detection in Memories - 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. | 05-06-2010 |
20100157642 | MITIGATION OF CHARGE SHARING IN MEMORY DEVICES - One embodiment relates to a memory element disposed on a substrate. The memory element includes first and second interlocked data storage elements adapted to cooperatively store the same datum. An output of the first data storage element is coupled to an input node of the second data storage element. An output of the second data storage element is coupled to an input of the first data storage element. An isolation element in the substrate is arranged laterally between storage nodes of the first and second data storage elements. The isolation element is arranged to limit charge sharing between the storage nodes of the first and second data storage elements. Other methods and systems are also disclosed. | 06-24-2010 |
20100208536 | Structure and Methods for Measuring Margins in an SRAM bit - 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. | 08-19-2010 |
20100232242 | Method for Constructing Shmoo Plots for SRAMS - 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. | 09-16-2010 |
20110013470 | Structure and Method for Screening SRAMS - An integrated circuit containing an SRAM that provides a switch to decouple the SRAM wordline voltage from the SRAM array voltage during screening and that also provides different wordline and array voltages during a portion of the SRAM bit screening test. A method for screening SRAM bits in an SRAM array in which the wordline voltage is different than the array voltage during a portion of the screening test. | 01-20-2011 |
20110051539 | Method and structure for SRAM VMIN/VMAX measurement - A parametric test circuit is disclosed (FIG. | 03-03-2011 |
20110051540 | Method and structure for SRAM cell trip voltage measurement - A parametric test circuit is disclosed (FIG. | 03-03-2011 |
20110158017 | METHOD FOR MEMORY CELL CHARACTERIZATION USING UNIVERSAL STRUCTURE - 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. The method further includes conducting a circuit element test on a circuit element in the set of circuit elements, where in the circuit element test the first and second supply nodes are not connected together, each terminal of the circuit element is directly forced with an electrical quantity, and an electrical quantity is directly measured from a terminal of the circuit element. Further, the method includes conducting at least one of a static noise margin test or a full cell test on the memory base cell. | 06-30-2011 |
20110158018 | Structure and Methods for Measuring Margins in an SRAM Bit - 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. | 06-30-2011 |
20110199806 | UNIVERSAL STRUCTURE FOR MEMORY CELL CHARACTERIZATION - An integrated circuit includes a structure, where the structure includes a memory base cell, a first port set, a second port set, and a set of other ports, where the memory base cell includes a first storage node set, a second storage node set, and a set of other nodes, 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 and are not connected together, where each node in the first storage node set is connected to a port in the first port set, where each node in the second storage node set is connected to a port in the second port set, where each of the other nodes is connected to one of the other ports, and where each of the other ports is connected to one and only one of the other nodes. | 08-18-2011 |
20110273946 | UNIVERSAL TEST STRUCTURES BASED SRAM ON-CHIP PARAMETRIC TEST MODULE AND METHODS OF OPERATING AND TESTING - An integrated circuit on-chip parametric (OCP) test structure includes a static random access memory (SRAM) universal test structure (UTS) having UTS ports and an OCP controller configured to determine first and second UTS ports of the SRAM UTS for independent connection to first and second on-chip test pads, respectively. The integrated circuit OCP test structure further includes a UTS OCP router connected to the OCP controller and configured to connect the first and second UTS ports of the SRAM UTS to the first and second on-chip test pads, respectively. Methods of operating an integrated circuit OCP test structure and OCP testing of an integrated circuit are also included. | 11-10-2011 |
20110299349 | Margin Testing of Static Random Access Memory Cells - 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. | 12-08-2011 |
20110317476 | Bit-by-Bit Write Assist for Solid-State Memory - A solid-state memory in which write assist circuitry is implemented within each memory cell. Each memory cell includes a storage element, such as a pair of cross-coupled inverters, that is connected in series with a pair of power switch transistors between a power supply node and ground. One of the power switch transistors is gated by a word line indicating selection of the row containing the cell, and the other is gated by a column select signal indicating selection of the column containing the cell in a write cycle. Upon a write to the cell, both power switch transistors are turned off, removing bias from the inverter that assists its change of state in a write operation. In other embodiments, a single power switch transistor gated by either a word line or a column select signal may be used. | 12-29-2011 |
20120014173 | Disturb-Free Static Random Access Memory Cell - A solid-state memory in which each memory cell includes a cross-point addressable write element. Each memory cell includes a storage element, such as a pair of cross-coupled inverters, and a read buffer for coupling one of the storage nodes to a read bit line for the column containing the cell. The write element of each memory cell includes one or a pair of write select transistors controlled by a write word line for the row containing the cell, and write pass transistors connected to corresponding storage nodes and connected in series with a write select transistor. The write pass transistors are gated by a write bit line for the column containing the cell. In operation, a write reference is coupled to one of the storage nodes of a memory cell in the selected column and the selected row, depending on the data state carried by the complementary write bit lines for that column. | 01-19-2012 |
20120014194 | Memory Cell with Equalization Write Assist in Solid-State Memory - A solid-state memory in which write assist circuitry is implemented within each memory cell. Each memory cell includes a storage element, such as a pair of cross-coupled inverters, and an equalization gate connected between the storage nodes of the storage element. The equalization gate may be realized by two transistors in series, or as a double-gate transistor. The equalization gate is controlled by a word line indicating selection of the row containing the cell in combination with a column select signal indicating selection of the column containing the cell in a write cycle. Upon a write to a selected cell, both gates are turned on, connecting the storage nodes of the cell to one another and assisting the write of the opposite date state from that previously stored. | 01-19-2012 |
20120014195 | SRAM with buffered-read bit cells and its testing - An SRAM with buffered-read bit cells is disclosed (FIGS. | 01-19-2012 |
20120106225 | Array-Based Integrated Circuit with Reduced Proximity Effects - 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. | 05-03-2012 |
20120224414 | Solid-State Memory Cell with Improved Read Stability - A solid-state memory in which stability assist circuitry is implemented within each memory cell. Each memory cell includes a storage element, such as a pair of cross-coupled inverters, and an isolation gate connected between one of the storage nodes and the input of the opposite inverter. The isolation gate may be realized by complementary | 09-06-2012 |
20130021864 | Array Power Supply-Based Screening of Static Random Access Memory Cells for Bias Temperature Instability - 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. | 01-24-2013 |
20130028036 | Method of Screening Static Random Access Memories for Unstable Memory Cells - 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. | 01-31-2013 |
20130044536 | ARRAY-BASED INTEGRATED CIRCUIT WITH REDUCED PROXIMITY EFFECTS - 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. | 02-21-2013 |
20130064007 | DISTURB-FREE STATIC RANDOM ACCESS MEMORY CELL - A solid-state memory in which each memory cell includes a cross-point addressable write element. Each memory cell includes a storage element, such as a pair of cross-coupled inverters, and a read buffer for coupling one of the storage nodes to a read bit line for the column containing the cell. The write element of each memory cell includes one or a pair of write select transistors controlled by a write word line for the row containing the cell, and write pass transistors connected to corresponding storage nodes and connected in series with a write select transistor. The write pass transistors are gated by a write bit line for the column containing the cell. In operation, a write reference is coupled to one of the storage nodes of a memory cell in the selected column and the selected row, depending on the data state carried by the complementary write bit lines for that column. | 03-14-2013 |
20130176772 | Electrical Screening of Static Random Access Memories at Varying Locations in a Large-Scale Integrated Circuit - A method of testing large-scale integrated circuits including multiple instances of memory arrays, and an integrated circuit structure for assisting such testing, are disclosed. In one embodiment, voltage drops due to parasitic resistance in array bias conductors are determined by extracting layout parameters, and subsequent circuit simulation that derives the voltage drops in those conductors during operation of each memory array. In another embodiment, sense lines from each memory array are selectively connected to a test sense terminal of the integrated circuit, at which the array bias voltage at each memory array is externally measured. Feedback control of the applied voltage to arrive at the desired array bias voltage can be performed. | 07-11-2013 |
20130182490 | Static Random Access Memory Cell with Single-Sided Buffer and Asymmetric Construction - 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. | 07-18-2013 |
20130182495 | Efficient Static Random-Access Memory Layout - A complementary metal-oxide-semiconductor (CMOS) static random access memory (SRAM) with no well contacts within the memory array. Modern sub-micron CMOS structures have been observed to have reduced vulnerability to latchup. Chip area is reduced by providing no well contacts within the array. Wells of either or both conductivity types may electrically float during operation of the memory. In other implementations, extensions of the array wells into peripheral circuitry may be provided, with well contacts provided in those extended portions. | 07-18-2013 |
20130294149 | REDUCING POWER IN SRAM USING SUPPLY VOLTAGE CONTROL - An embodiment of the invention provides a method for decreasing power in a static random access memory (SRAM). A first voltage is applied between latch sourcing and latch sinking supply lines for columns of memory cells that are column addressed during a read cycle. A second voltage is applied between latch sourcing and latch sinking supply lines for columns of memory cells that are not column addressed during a read cycle. Because the second voltage is less than the first voltage, power in the SRAM is reduced. In this embodiment, a memory cell in the SRAM includes at least one read buffer and a latch connected between the latch sourcing and latch sinking supply lines. | 11-07-2013 |
20130320458 | Static Random-Access Memory Cell Array with Deep Well Regions - 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. | 12-05-2013 |
20130343136 | SRAM WITH BUFFERED-READ BIT CELLS AND ITS TESTING - An SRAM with buffered-read bit cells is disclosed (FIGS. | 12-26-2013 |
20140078819 | STATIC RANDOM ACCESS MEMORY CELL WITH SINGLE-SIDED BUFFER AND ASYMMETRIC CONSTRUCTION - 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. | 03-20-2014 |
20140126277 | SRAM WITH BUFFERED-READ BIT CELLS AND ITS TESTING - An SRAM with buffered-read bit cells is disclosed ( | 05-08-2014 |