Nscore, Inc.

Nec Electronics Corporation

Kenji Noda

Takashi Kikuchi

Tadahiko Horiuchi

A nonvolatile memory device includes a pair of MIS transistors one of which is placed in a programmed state by a first program operation utilizing a hot carrier effect to store one-bit data in the pair of MIS transistors, and a control unit configured to recall the one-bit data from the pair of MIS transistors in a recall operation, to cause an unprogrammed one of the MIS transistors to be placed in a programmed state by a second program operation utilizing a hot carrier effect in response to the one-bit data recalled from the pair of MIS transistors, and to erase the programmed states of both of the MIS transistors in an erase operation.

MIS transistors configured to be placed in programmed state and erased state

A nonvolatile memory device includes a pair of PMOS transistors, and a control circuit configured to operate in a store mode to apply to a first one of the PMOS transistors potentials that cause an NBTI degradation purposefully and to apply to a second one of the PMOS transistors potentials that cause no NBTI degradation while causing no current to flow between a source node and a drain node of the first one of the PMOS transistors, and to operate in a recall mode to set gate nodes of the PMOS transistors to a common potential to detect a difference in the NBTI degradation between said PMOS transistors.

Nonvolatile memory device storing data based on change in transistor characteristics

A memory circuit includes a latch having a first node and a second node to store data such that a logic level of the first node is an inverse of a logic level of the second node, a MIS transistor having a gate node, a first source/drain node, and a second source/drain node, the first source/drain node coupled to the first node of the latch, and a control circuit configured to control the gate node and second source/drain node of the MIS transistor to make an upward lingering change in a threshold voltage of the MIS transistor in a first operation in response to data stored in the latch and to make a downward lingering change in the threshold voltage in a second operation in response to data stored in the latch.

MIS-transistor-based nonvolatile memory for multilevel data storage

A nonvolatile semiconductor memory device includes a latch circuit having two nodes, a nonvolatile memory cell including two MIS transistors, a bit swapping unit configured to provide straight connections between the two nodes and the two MIS transistors during a first operation mode and to provide cross connections between the two nodes and the two MIS transistors during a second operation mode, and a control circuit configured to cause, in one of the first and second operation modes, the nonvolatile memory cell to store the data latched in the latch circuit as an irreversible change of transistor characteristics occurring in a selected one of the two MIS transistors, and further configured to cause, in another one of the first and second operation modes, the latch circuit to detect the data stored in the nonvolatile memory cell.

Nonvolatile memory utilizing MIS memory transistors with function to correct data reversal

A nonvolatile semiconductor memory device includes a latch circuit including a first inverter and a second inverter cross-coupled to each other, a source node of a MIS transistor of the first inverter and a source node of a MIS transistor of the second inverter being both coupled to a plate line, and a control circuit configured to apply a first potential to the plate line in a store mode to cause a change in threshold voltage to one of the MIS transistors, and configured to apply a second potential to the plate line in a power-on mode to cause the latch circuit to latch data responsive to the change in threshold voltage generated in the store mode, such that the data latched by the latch circuit in the power-on mode is automatically output to outside the nonvolatile semiconductor memory device upon power-on thereof.

MIS-transistor-based nonvolatile memory

To provide wiring structure and method capable of supplying a scan clock signal for each clock domain without requesting a user to add a test circuit. The wiring structure of a semiconductor integrated circuit according to an embodiment of the present invention includes: a fixed layer where a common line independent of a user circuit is formed; and a customized layer which is formed on the fixed layer and in which a line dependent on the user circuit is formed. The fixed layer is provided with a scan clock line supplying a scan clock signal for scan test to the selecting circuit, and a clock line supplying an output signal of the selecting circuit to a flip-flop of a scan path, and the customized layer is provided with a user clock line supplying a user clock signal to the selecting circuit.

Wiring structure and method of semiconductor integrated circuit

A nonvolatile semiconductor memory device includes a latch configured to store data, a plurality of word lines, a driver configured to activate one of the plurality of word lines, and a plurality of nonvolatile memory cells coupled to the respective word lines, each of the nonvolatile memory cells coupled to the latch so as to exchange stored data with the latch upon activation of a corresponding one of the word lines, each of the nonvolatile memory cells including two MIS transistors and configured to store data as an irreversible change of transistor characteristics occurring in one of the two MIS transistors, wherein the driver includes at least one nonvolatile memory cell storing count data responsive to a number of times storing of data has been performed with respect to the plurality of nonvolatile memory cells, and is configured to activate one of the word lines indicated by the count data.

Nonvolatile memory utilizing MIS memory transistors capable of multiple store operations

A nonvolatile semiconductor memory device includes a control circuit, an inverting circuit, and memory units, each of the memory units including a latch having a first node and a second node, a plate line, a first MIS transistor having one of source/drain nodes coupled to the first node of the latch, another one of the source/drain nodes coupled to the plate line, and a gate node coupled to a word line, and a second MIS transistor having one of source/drain nodes coupled to the second node of the latch, another one of the source/drain nodes coupled to the plate line, and a gate node coupled to the word line, wherein the control circuit is configured to invert the data latched in the latch by reading the data from the latch, causing the inverting circuit to invert the read data, and writing the inverted data to the latch.

Nonvolatile memory utilizing hot-carrier effect with data reversal function

A nonvolatile semiconductor memory device includes a memory cell having a MIS transistor configured to experience an irreversible change in transistor characteristics thereof to store data as the irreversible change, the MIS transistor having a gate node coupled to a word selecting line and a source/drain node coupled to a bit line, and the MIS transistor becoming conductive in response to a first state of the word selecting line and becoming nonconductive in response to a second state of the word selecting line, and a test circuit coupled to the bit line to sense a current running through the MIS transistor, the test circuit configured to indicate error in response to either a detection of presence of the current when the word selecting line is in the second state or a detection of absence of the current when the word selecting line is in the first state.

Nonvolatile memory device with test mechanism

A memory circuit includes a latch having a first node and a second node, a first MIS transistor operable to couple between the first node and a predetermined node, a second MIS transistor operable to couple between the second node and the predetermined node, and a control circuit configured to subject one of the first MIS transistor and the second MIS transistor to bias conditions that cause a lingering change in transistor characteristics thereof, wherein the MIS transistors of the latch have a lightly-doped-drain structure that includes first diffusion regions having a first impurity concentration and second diffusion regions having a second impurity concentration smaller than the first impurity concentration, and each of the first MIS transistor and the second MIS transistor has a doped diffusion region closest to a conduction channel with an impurity concentration different from the second impurity concentration.

Hot-carrier-based nonvolatile memory utilizing differing transistor structures

A memory circuit includes a latch having a first node and a second node, a first MIS transistor having source/drain nodes thereof coupled to the first node and to a plate line, respectively, and a gate node thereof coupled to a word selecting line, a second MIS transistor having source/drain nodes thereof coupled to the second node and to the plate line, respectively, and a gate node thereof coupled to the word selecting line, and a driver circuit configured to set the plate line to a first potential causing the first node to serve as a source node of the first MIS transistor in a first operation mode and to a second potential causing the first node to serve as a drain node of the first MIS transistor in a second operation mode, the first operation mode causing a lingering change in characteristics of the first MIS transistor.

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Fukuoka, Japan

Kenji Noda