Semiconductor non-volatile DRAM (NVDRAM) device
First Claim
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1. A semiconductor device comprising:
- a plurality of word lines;
a plurality of bit lines; and
a plurality of memory cells coupled to the word lines and the bit lines,wherein each of the memory cells comprises;
a DRAM cell including a capacitor to hold information at a storage node and a first control transistor;
a nonvolatile memory cell to hold information by use of a first threshold voltage as an erase state and a second threshold voltage as a write state, and to shift to the write state by a write voltage being applied in the erase state; and
a first transistor to select whether or not to apply the write voltage to the nonvolatile memory cell according to the voltage level at the storage node of the DRAM cell.
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Abstract
A semiconductor device that can evacuate the information in a DRAM automatically at the time of power supply cutoff is provided. A memory cell includes a DRAM cell that holds information at a storage node, a nonvolatile memory cell, and a transistor. The nonvolatile memory cell holds information by use of the first threshold voltage as an erase state and the second threshold voltage as a write state, and shifts to the write state by a write voltage being applied in the erase state. The transistor selects whether or not to apply the write voltage (voltage of a write voltage line) to the nonvolatile memory cell according to the voltage level at the storage node of the DRAM cell.
4 Citations
17 Claims
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1. A semiconductor device comprising:
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a plurality of word lines; a plurality of bit lines; and a plurality of memory cells coupled to the word lines and the bit lines, wherein each of the memory cells comprises; a DRAM cell including a capacitor to hold information at a storage node and a first control transistor; a nonvolatile memory cell to hold information by use of a first threshold voltage as an erase state and a second threshold voltage as a write state, and to shift to the write state by a write voltage being applied in the erase state; and a first transistor to select whether or not to apply the write voltage to the nonvolatile memory cell according to the voltage level at the storage node of the DRAM cell. - View Dependent Claims (2, 3, 4)
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5. A semiconductor device supplied with a low-potential-side power supply voltage and a high-potential-side power supply voltage, the semiconductor device comprising:
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a plurality of word lines; a plurality of bit lines; a plurality of memory cells coupled to the word lines and the bit lines; and a write-back control line, wherein each of the memory cells comprises; a DRAM cell including a capacitor to hold information at a storage node and a first control transistor to couple a predetermined bit line to the storage node in response to activation of a predetermined word line; a nonvolatile memory cell to hold information by use of a first threshold voltage as an erase state and a second threshold voltage as a write state, and to shift to the write state by a write voltage being applied in the erase state; a first transistor to select whether or not to apply the write voltage to the nonvolatile memory cell according to the voltage level at the storage node of the DRAM cell; and a second transistor coupled between the storage node and the nonvolatile memory cell and to write back information read from the nonvolatile memory cell to the storage node in response to activation of the write-back control line. - View Dependent Claims (6, 7, 8, 9, 10, 11)
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12. A semiconductor device supplied with a low-potential-side power supply voltage and a high-potential-side power supply voltage, the semiconductor device comprising:
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a plurality of word lines; a plurality of bit lines; a plurality of sense amplifier circuits coupled to the bit lines and to amplify voltages of the bit lines; a plurality of memory cells coupled to the word lines and the bit lines; and a write-back control line, wherein each of the memory cells comprises; a DRAM cell including a capacitor to hold information at a storage node and a first control transistor to couple a predetermined bit line to the storage node in response to activation of a predetermined word line; a nonvolatile memory cell to hold information by use of a first threshold voltage as an erase state and a second threshold voltage as a write state, and to shift to the write state by a write voltage being applied in the erase state; a first transistor to select whether or not to apply the write voltage to the nonvolatile memory cell according to the voltage level at the storage node of the DRAM cell; a second control transistor having one end coupled to the predetermined bit line, and controlled to an ON state in response to activation of the predetermined word line; and a second transistor coupled between the other end of the second control transistor and the nonvolatile memory cell and to transmit information read from the nonvolatile memory cell to the second control transistor in response to activation of the write-back control line. - View Dependent Claims (13, 14, 15, 16, 17)
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Specification