Abstract: A nonvolatile semiconductor memory device includes a first latch to store data, a nonvolatile memory cell including two MIS transistors to store data as an irreversible change of transistor characteristics occurring in one of the two MIS transistors selected in response to the data stored in the first latch, a second latch to store data obtained by sensing a difference in the transistor characteristics between the two MIS transistors, a logic circuit to produce a signal indicative of comparison between the data of the first latch and the data of the second latch, and a control circuit configured to repeat a store operation storing data in the nonvolatile memory cell, a recall operation storing data in the second latch, and a verify operation producing the signal indicative of comparison until the signal indicates that the data of the first latch and the data of the second latch are the same.

Abstract: 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.

Abstract: A nonvolatile semiconductor memory device includes a data input buffer configured to receive data from outside the device, a nonvolatile memory cell including two MIS transistors to store first data received by the data input buffer by creating an irreversible change of transistor characteristics in one of the two MIS transistors, whichever is selected in response to a value of the first data, a sense latch coupled to the nonvolatile memory cell and configured to store the first data obtained by sensing a difference in the transistor characteristics between the two MIS transistors of the nonvolatile memory cell, and a logic circuit configured to produce a signal indicative of comparison between the first data stored in the sense latch and second data received by the data input buffer, wherein no data path to output the first data stored in the sense latch to outside the nonvolatile semiconductor memory device exists.

Abstract: A nonvolatile semiconductor memory device includes a plurality of control lines, a control circuit configured to assert selected ones of the control lines, and a plurality of memory cell arranged in rows and columns and including respective latch circuits and respective nonvolatile memory cells, wherein the memory cell units are configured to perform a write operation in which the latch circuits of the memory cell units on a selected row store respective bits of the input data, and are further configured to perform a store operation in which the respective bits of the input data are transferred from the latch circuits to the nonvolatile memory cells for storage therein in response to assertion of respective control lines by the control circuit, so that only one or more selective bits of the input data selected by the control circuit are stored in the nonvolatile memory cells.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A nonvolatile memory circuit includes a flip-flop to degrade an internal circuit irreversibly based on a voltage applied to a first or second bit line so as to latch data in a nonvolatile manner, a first switch coupled between a first output terminal of the flip-flop and the first bit line, a second switch coupled between the first output terminal of the flip-flop and the first bit line, a third switch coupled between a second output terminal of the flip-flop outputting an inverse of an output of the first output terminal and the second bit line, and a fourth switch coupled between the second output terminal of the flip-flop and the second bit line.

Abstract: A nonvolatile semiconductor memory circuit includes a selection line, a first bit line, a second bit line, a first MIS transistor having a first gate coupled to the selection line, a first drain coupled to the first bit line via a first node, and a first source coupled to a predetermined potential, a second MIS transistor having a second gate coupled to the selection line, a second drain coupled to the second bit line via a second node, and a second source coupled to the predetermined potential, and a latch circuit coupled to the first node and the second node to store data responsive to a signal difference between the first node and the second node, wherein the selection line is operative to supply a write potential that creates a lingering change in a threshold voltage of one of the first MIS transistor and the second MIS transistor.

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

Abstract: A nonvolatile semiconductor memory circuit includes a selection line, a first bit line, a second bit line, a first MIS transistor having a first gate coupled to the selection line, a first drain coupled to the first bit line via a first node, and a first source coupled to a predetermined potential, a second MIS transistor having a second gate coupled to the selection line, a second drain coupled to the second bit line via a second node, and a second source coupled to the predetermined potential, and a latch circuit coupled to the first node and the second node to store data responsive to a signal difference between the first node and the second node, wherein the selection line is operative to supply a write potential that creates a lingering change in a threshold voltage of one of the first MIS transistor and the second MIS transistor.

Abstract: A memory circuit includes a latch having a first node and a second node, a word selecting line, a first MIS transistor having the source/drain nodes thereof coupled to the first node and a predetermined node, respectively, and the gate node thereof coupled to the word selecting line, a second MIS transistor having the source/drain nodes thereof coupled to the second node and the predetermined node, respectively, and the gate node thereof coupled to the word selecting line, and a control circuit configured to subject in a write mode, one of the first MIS transistor and the second MIS transistor to bias conditions that cause a lingering change in transistor characteristics thereof, and to subject in a recovery mode both the first MIS transistor and the second MIS transistor for equal amount of time to equal bias conditions that cause a lingering change in transistor characteristics thereof.