Semiconductor integrated circuit device with reduced leakage current
The gate tunnel leakage current is increased in the up-to-date process, so that it is necessary to reduce the gate tunnel leakage current in the LSI which is driven by a battery for use in a cellular phone and which needs to be in a standby mode at a low leakage current. In a semiconductor integrated circuit device, the ground source electrode lines of logic and memory circuits are kept at a ground potential in an active mode, and are kept at a voltage higher than the ground potential in an unselected standby mode. The gate tunnel leakage current can be reduced without destroying data.
1. A semiconductor integrated circuit device comprising:
a memory cell array including a plurality of memory cells arranged in a matrix having rows and columns;
word lines provided for the rows, respectively;
data line pairs provided for the columns, respectively;
a source line connected to the plurality of memory cells, and a potential control circuit configured to control a potential of the source line,
wherein each of the plurality of memory cells includes;
a first P-channel MOS transistor having a gate electrode connected to a first storage node, a drain electrode connected to a second storage node and a source electrode to which a power supply voltage is applied,
a second P-channel MOS transistor having a gate electrode connected to the second storage node, a drain electrode connected to the first storage node and a source electrode to which the power supply voltage is applied,
a first N-channel MOS transistor having a gate electrode connected to the first storage node, a drain electrode connected to the second storage node and a source electrode connected to the source line,
a second N-channel MOS transistor having a gate electrode connected to the second storage node, a drain electrode connected to the first storage node and a source electrode connected to the source line;
a third N-channel MOS transistor making a current pass between the first storage node and one data line of one data line pair of the data line pairs and having a gate electrode connected to one of the word lines, and
a fourth N-channel MOS transistor making a current pass between the second storage node and another data line of the one data line pair of the data line pairs and having a gate electrode connected to the one of the word lines,
wherein the potential control circuit controls the potential of the source line to a first potential value in a operation state and to a second potential value larger than the first potential value in an standby state, so that a first leakage current flows through one of the first P-channel MOS transistor and the second P-channel MOS transistor in an OFF state and a first leakage current flows through one of the second N-channel transistor and the second N-channel MOS transistor in the OFF state can be reduced in the standby state compared to in the operation state.
2. The semiconductor integrated circuit device according to claim 1 ,
wherein the first and second leak currents include a Gate Induced Drain Leak (GIDL) current between a drain electrode and a substrate electrode of each of the corresponding P-channel and N-channel MOS transistors.
3. The semiconductor integrated circuit device according to claim 2 ,
wherein both data lines of each of the data line pairs are configured to have a potential value lower than the power supply voltage of the respective source electrodes of the first and second p-channel MOS transistors when the potential of the source line has the second potential value.
4. The semiconductor integrated circuit device according to claim 2 ,
wherein both data lines of each of the data line pairs are configured to have a potential value between the power supply voltage and the second potential value when the potential of the source line has the second potential value, and
wherein the GIDL currents flowing through both the third N-channel MOS transistor and the fourth N-channel MOS transistor can be reduce in the standby state compared to in the operation state.
5. The semiconductor integrated circuit device according to claim 1 , further comprising:
word drivers connected to the word lines, respectively, and providing the connected word lines with the first potential value when the potential of the source line has the second potential value.
6. The semiconductor integrated circuit device according to claim 5 ,
wherein both data lines of each of the data line pairs are configured to have a potential value higher than the second potential value when the source line has the second potential value.
7. The semiconductor integrated circuit device according to claim 5 ,
wherein both data lines of each of the data line pairs are configured to have a potential value higher than the second potential value but lower than the power supply voltage when the potential of the source line has the second potential value, and
wherein the GIDL currents flowing through both the third N-channel MOS transistor and the fourth N-channel MOS transistor can be reduce in the standby state compared to in the operation state.
8. The semiconductor integrated circuit device according to claim 1 ,
wherein substrate electrodes of the first to fourth n-channel MOS transistors have a voltage of the first potential value when the potential of the source line has the first potential value or the second potential value.
9. The semiconductor integrated circuit device according to claim 1 ,
wherein each of the first and second P-channel MOS transistors has a gate insulation film of a 4 nm or less thickness, and each of the first to fourth N-channel MOS transistors has a gate insulation film of a 4 nm or less thickness.
10. A semiconductor integrated circuit device comprising:
memory cells;
word lines and pairs of data lines coupled to the memory cells so that one memory cell is coupled to one word line and one pair of data lines;
word drivers coupled to the word lines, respectively;
precharge circuits coupled to the pairs of data lines, respectively;
a power supply line for a power supply voltage (VDD);
a source line coupled to the memory cells, and
a potential control circuit coupled to the source line,
wherein each of the memory cells includes;
a first P-channel MOS transistor having a gate coupled to a first storage node, a drain coupled to a second storage node and a source to which the power supply voltage is applied,
a second P-channel MOS transistor having a gate coupled to the second storage node, a drain coupled to the first storage node and a source to which the power supply voltage is applied,
a first N-channel MOS transistor having a gate coupled to the first storage node, a drain coupled to the second storage node and a source coupled to the source line,
a second N-channel MOS transistor having a gate coupled to the second storage node, a drain coupled to the first storage node and a source coupled to the source line;
a third N-channel MOS transistor having a source-drain path coupled between the first storage node and one data line of the corresponding one pair of data lines and a gate coupled to one of the word lines, and
a fourth N-channel MOS transistor having a source-drain path coupled between the second storage node and another data line of the corresponding one pair of data lines and a gate coupled to the one of the word lines,
wherein the potential control circuit provides to the source line a first voltage in an operation state and provides to the source line a second voltage between the power supply voltage and the first voltage in a standby state,
wherein the word drivers provide the first voltage to the word lines in the standby state, and
wherein the precharge circuits provide the power supply voltage to the pairs of data lines in an operation state and provide a third voltage between the power supply voltage and the second voltage to the pairs of data lines in a standby state.
11. The semiconductor integrated circuit device according to claim 10 ,
wherein GIDL (Gate Induced Drain Leakage) currents, gate tunnel leakage currents and subthreshold leakage currents flowing thought the memory cells are reduced in the standby mode compared to in the operation state.
12. The semiconductor integrated circuit device according to claim 10 ,
wherein substrates of the first to fourth n-channel MOS transistors have the first voltage in the operation mode and in the standby mode.
13. The semiconductor integrated circuit device according to claim 12 ,
wherein GIDL (Gate Induced Drain Leakage) currents, gate tunnel leakage currents and subthreshold leakage currents flowing thought the memory cells are reduced in the standby mode compared to in the operation state.
14. The semiconductor integrated circuit device according to claim 13 ,
wherein each of the first and second P-channel MOS transistors has a gate insulation film of a 4 nm or less thickness, and
wherein each of the first to fourth N-channel MOS transistors has a gate insulation film of a 4 nm or less thickness.
15. The semiconductor integrated circuit device according to claim 10 ,
wherein each of the first and second P-channel MOS transistors has a gate insulation film of a 4 nm or less thickness, and
wherein each of the first to fourth N-channel MOS transistors has a gate insulation film of a 4 nm or less thickness.