Low power programming technique for a floating body memory transistor, memory cell, and memory array
View Patent ↗There are many inventions described and illustrated herein. In one aspect, the present invention is directed to a memory cell, architecture, and/or array and/or technique of writing or programming data into the memory cell (for example, a technique to write or program a logic low or State “0” in a memory cell employing an electrically floating body transistor. In this regard, the present invention programs a logic low or State “0” in the memory cell while the electrically floating body transistor is in the “OFF” state or substantially “OFF” state (for example, when the device has no (or practically no) channel and/or channel current between the source and drain). In this way, the memory cell may be programmed whereby there is little to no current/power consumption by the electrically floating body transistor and/or from memory array having a plurality of electrically floating body transistors.
1. A dynamic random access memory cell for storing a first data state and a second data state, the memory cell comprising:
an electrically floating body transistor having:
a source region;
a drain region;
a body region disposed between the source region and the drain region,
wherein the body region is electrically floating; and
a gate spaced apart from, and capacitively coupled to, the body region;
wherein the electrically floating body transistor includes a first data state representative of a first amount of majority carriers in the body region, and a second data state representative of a second amount of majority carriers in the body region, wherein the first amount of majority carriers is less than the second amount of majority carriers;
wherein the first data state is provided by applying a first voltage to the gate, a second voltage to the drain region, a third voltage to the source region such that, in response to the first, second and third voltages, the electrically floating body transistor is off or substantially off; and
wherein the second voltage is greater than the first voltage and the absolute value of the difference between the first voltage and the third voltage is less than the absolute value of the threshold voltage of the electrically floating body transistor.
2. The dynamic random access memory cell of claim 1 wherein the first and third voltages have the same voltage amplitude.
3. The dynamic random access memory cell of claim 1 wherein the electrically floating body transistor is an N-channel type transistor or a P-channel type transistor.
4. The dynamic random access memory cell of claim 1 the electrically floating body transistor includes a layout, a geometry or electrical characteristics that provides sufficient capacitive coupling between the drain and the floating body such that, in response to the first, second and third voltages, majority carriers are removed from the body region through source region.
5. The dynamic random access memory cell of claim 1 wherein the absolute value of the difference between the first voltage and the third voltage is substantially less than the absolute value of the threshold voltage of the electrically floating body transistor.
6. The dynamic random access memory cell of claim 1 wherein the absolute value of the difference between the second voltage and the first voltage is greater than one volt.
7. The dynamic random access memory cell of claim 1 wherein the second data state which is representative of a second amount of majority carriers in the body region is substantially provided by impact ionization.
8. The dynamic random access memory cell of claim 1 wherein the first and third voltages are the same voltage.
9. The dynamic random access memory cell of claim 1 wherein the second data state is substantially provided by (i) band-to-band tunneling of majority carriers from the drain region to the body region, or (ii) band-to-band tunneling of majority carriers from the source region to the body region.
10. A dynamic random access memory cell for storing a first data state and a second data state, the memory cell comprising:
an electrically floating body transistor having:
a source region;
a drain region;
a body region disposed between the source region and the drain region,
wherein the body region is electrically floating; and
a gate spaced apart from, and capacitively coupled to, the body region;
wherein the electrically floating body transistor includes a first data state representative of a first amount of majority carriers in the body region, and a second data state representative of a second amount of majority carriers in the body region, wherein the first amount of majority carriers is less than the second amount of majority carriers; and
wherein the first data state is provided by applying a first voltage to the gate, a second voltage to the drain region, a third voltage to the source region such that, in response to the first, second and third voltages the electrically floating body transistor is off or substantially off.
11. The dynamic random access memory cell of claim 10 wherein the electrically floating body transistor is off when there is no or substantially no channel and/or channel current between the source and drain regions of the electrically floating body transistor.
12. The dynamic random access memory cell of claim 10 wherein the electrically floating body transistor is an N-channel type transistor or a P-channel type transistor.
13. The dynamic random access memory cell of claim 10 the electrically floating body transistor includes a layout, a geometry or electrical characteristics that provides sufficient capacitive coupling between the drain and the floating body such that, in response to the first, second and third voltages, majority carriers are removed from the body region through drain region.
14. The dynamic random access memory cell of claim 10 wherein the absolute value of the difference between the first voltage and the second voltage is substantially less than the absolute value of the threshold voltage of the electrically floating body transistor.
15. The dynamic random access memory cell of claim 10 wherein the absolute value of the difference between the third voltage and the first voltage is greater than one volt.
16. The dynamic random access memory cell of claim 10 wherein the second data state which is representative of a second amount of majority carriers in the body region is substantially provided by impact ionization.
17. The dynamic random access memory cell of claim 10 wherein the first and second voltages have the same amplitude.
18. The dynamic random access memory cell of claim 10 wherein the second data state is substantially provided by (i) band-to-band tunneling of majority carriers from the source region to the body region, or (ii) band-to-band tunneling of majority carriers from the drain region to the body region.
19. A method of controlling a dynamic random access memory cell comprising an electrically floating body transistor having a source region, a drain region, a body region disposed between the source region and the drain region, wherein the body region is electrically floating; and a gate spaced apart from, and capacitively coupled to, the body region, the method comprising:
applying a first voltage to the gate;
applying a second voltage to the drain region;
applying a third voltage to the source region, wherein, in response to the first, second and third voltages, the electrically floating body transistor is off or substantially off; and
wherein, in response to the first, second and third voltages, a substantial amount of the majority carriers are removed from the body region through the source region or the drain region to provide a first data state having a first amount of majority carriers in the body region, wherein the first data state is different than a second data state of the electrically floating body transistor in that the first amount of majority carriers is less than the amount of majority carriers in the body region when the electrically floating body transistor is in the second data state.
20. The method of claim 19 wherein the absolute value of the difference between the first voltage and the second voltage is greater than one volt.
21. The method of claim 19 wherein the difference between the first voltage and the second voltage is substantially less than the threshold voltage of the electrically floating body transistor.
22. The method of claim 19 wherein the second data state which is representative of a second amount of majority carriers in the body region is substantially provided by impact ionization.
23. The method of claim 19 wherein the first and third voltages have the same amplitude.
24. The method of claim 19 wherein the second data state is substantially provided by (i) band-to-band tunneling of majority carriers from the source region to the body region, or (ii) band-to-band tunneling of majority carriers from the drain region to the body region.