Refreshing data of memory cells with electrically floating body transistors
View Patent ↗A semiconductor device along with circuits including the same and methods of operating the same are described. The device comprises a memory cell including one transistor. The transistor comprises a gate, an electrically floating body region, and a source region and a drain region adjacent the body region. Data stored in memory cells of the device can be refreshed within a single clock cycle.
1. An integrated circuit device comprising:
a plurality of memory cells each comprising a transistor having a body region configured to be electrically floating for storing data; and
refresh circuitry coupled to the plurality of memory cells, the refresh circuitry configured to refresh data stored in each transistor by reading the data from the transistor and writing the data to the transistor during a single clock cycle with no intervening hold state therebetween.
2. The integrated circuit device of claim 1 , the refresh circuitry reads the data from the transistor by applying read control signals to the transistor.
3. The integrated circuit device of claim 2 , the refresh circuitry writes the data to the transistor by applying one of first write control signals and second write control signals to the transistor.
4. The integrated circuit device of claim 3 , wherein one of the first write control signals and the second write control signals are applied to the transistor immediately following the application of the read control signals depending upon a data state detected in the transistor as a result of the application of the read control signals.
5. The integrated circuit device of claim 3 , wherein the read control signals perform a read operation on the transistor during a first portion of the single clock cycle.
6. The integrated circuit device of claim 5 , wherein the first write control signals perform a first write operation on the transistor during a second portion of the single clock cycle, wherein the first write operation comprises writing a logic high data state to the transistor if a logic high data state is detected in the transistor as a result of the application of the read control signals.
7. The integrated circuit device of claim 5 , wherein the second write control signals perform a second write operation on the transistor during a second portion of the single clock cycle, wherein the second write operation comprises writing a logic low data state to the transistor if a logic low data state is detected in the transistor as a result of the application of the read control signals.
8. The integrated circuit device of claim 3 , wherein the transistor further comprises a gate, a source region, and a drain region, wherein the gate is capacitively coupled to the body region, and wherein the source region and the drain region are disposed on opposing sides of the body region.
9. The integrated circuit device of claim 8 , wherein the refresh circuitry comprises a read-word line coupled to the gate and a read-bit output coupled to the source region or the drain region.
10. The integrated circuit device of claim 9 , wherein the body region stores data in the form of a charge accumulated in the body region.
11. The integrated circuit device of claim 10 , wherein, in response to the read control signals, the transistor imparts the data onto the read-bit line by discharging the body region in response to a shifting voltage level on the read-word line.
12. The integrated circuit device of claim 11 , wherein the shifting voltage level on the read-word line provides a gate-to-source voltage sufficient to cause read-bit line charging or lack of charging depending upon a data state detected in the transistor as a result of the application of the read control signals.
13. The integrated circuit device of claim 12 , wherein the discharging provides a read current on the read-bit line that is proportional to a current gain of the transistor multiplied by the charge.
14. The integrated circuit device of claim 13 , wherein the refresh circuitry determines the data state stored in the transistor at least substantially based on the read current.
15. The integrated circuit device of claim 11 , wherein the transistor further imparts the data onto the read-bit line by discharging the body region in response to a shifting voltage level on a read-source line coupled to the source region or the drain region.
16. The integrated circuit device of claim 8 , wherein the gate is disposed over a first portion of the body region.
17. The integrated circuit device of claim 16 , wherein the source region adjoins a second portion of the body region that is adjacent the first portion and separates the source region from the first portion.
18. The integrated circuit device of claim 17 , wherein the drain region adjoins a third portion of the body region that is adjacent the first portion and separates the drain region from the first portion.
19. The integrated circuit device of claim 1 , wherein the body region functions as an inherent bipolar transistor.
20. An integrated circuit device comprising:
a plurality of memory cells each comprising a transistor having a gate, a body region configured to be electrically floating for storing data, and a source region and a drain region adjacent the body region; and
refresh circuitry coupled to the plurality of memory cells, the refresh circuitry configured to refresh data stored in each transistor by reading the data from the transistor and writing the data to the transistor during a single clock cycle with no intervening hold state therebetween.