Discrete devices including EAPROM transistor and NVRAM memory cell with edge defined ferroelectric capacitance, methods for operating same, and apparatuses including same
First Claim
1. A one transistor/one capacitor (1T/1C) memory cell comprising an edge defined ferroelectric capacitor operatively coupled to the gate electrode of a charge amplifier transistor by a polysilicon interconnect, wherein the edge defined ferroelectric capacitor is in a stacked alignment with an active gate oxide channel region of the transistor.
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Abstract
A memory cell includes a charge amplifier having a gate adjacent to a channel region coupling source and drain regions, a digitline coupled to one of the source and drain regions, a ground lead coupled to the other of the source and drain regions, a ferroelectric capacitor coupled to the gate, and a wordline coupled to the ferroelectric capacitor. Advantageously, the charge amplifier can be a CMOS transistor. Preferably, the gate is coupled to the ferroelectric capacitor by polysilicon, the junction formed at the gate has an intrinsic capacitance, and the capacitance of the ferroelectric capacitor is based on the magnitude of the intrinsic capacitance. Alternatively, the gate is coupled to the ferroelectric capacitor by polysilicon, the junction formed at the gate has an intrinsic capacitance, and the physical size of the ferroelectric capacitor is based on the magnitude of the intrinsic capacitance. In this case, the thickness of a ferroelectric material layer in the ferroelectric capacitor can be based on the magnitude of the intrinsic capacitance. A memory cell array, a memory module, and a processor based system can all be fabricated from this memory cell. Methods for reading data out of and writing data into the memory cell are also described.
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Citations
55 Claims
- 1. A one transistor/one capacitor (1T/1C) memory cell comprising an edge defined ferroelectric capacitor operatively coupled to the gate electrode of a charge amplifier transistor by a polysilicon interconnect, wherein the edge defined ferroelectric capacitor is in a stacked alignment with an active gate oxide channel region of the transistor.
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5. A memory cell comprising:
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a charge amplifier comprising a gate adjacent to a channel region coupling source and drain regions;
a digitline coupled to one of the source and drain regions;
source line coupled to the other of the source and drain regions;
an edge defined ferroelectric capacitor coupled to the gate by a polysilicon interconnect; and
a wordline coupled to the edge defined ferroelectric capacitor, wherein the edge defined ferroelectric capacitor is in a stacked alignment with an active oxide channel region of the charge amplifier. - View Dependent Claims (6, 7, 8, 9, 10)
the junction formed at the gate has an intrinsic capacitance; and
the capacitance of the ferroelectric capacitor is based on the magnitude of the intrinsic capacitance.
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9. The memory cell as recited in claim 5, wherein:
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the junction formed at the gate has an intrinsic capacitance; and
the physical size of the ferroelectric capacitor is based on the magnitude of the intrinsic capacitance.
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10. The memory cell as recited in claim 9, wherein the thickness of a ferroelectric material layer in the ferroelectric capacitor is based on the magnitude of the intrinsic capacitance.
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11. A memory cell comprising:
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a charge amplifier comprising a gate opposing a channel region coupling source and drain regions;
a digitline coupled to the drain region;
a source line coupled to the source region;
an edge defined ferroelectric capacitor coupled to the gate by a polysilicon interconnect, the edge defined ferroelectric capacitor being configured to store data; and
a wordline coupled to the gate by the edge defined ferroelectric capacitor, wherein the edge defined ferroelectric capacitor is in a stacked alignment with an active gate oxide channel region of the charge amplifier. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 45)
the junction formed at the gate has an intrinsic capacitance; and
the capacitance of the ferroelectric capacitor is based on the magnitude of the intrinsic capacitance.
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15. The memory cell as recited in claim 11, wherein:
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the junction formed at the gate has an intrinsic capacitance; and
the physical size of the ferroelectric capacitor is based on the magnitude of the intrinsic capacitance.
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16. The memory cell as recited in claim 11, wherein the ferroelectric capacitor is an edge defined ferroelectric capacitor.
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17. The memory cell as recited in claim 16, wherein the edge defined ferroelectric capacitor comprises a dielectric layer of lead zirconate titanate (PZT).
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18. The memory cell as recited in claim 11, wherein the ferroelectric capacitor comprises a dielectric layer of lead zirconate titanate (PZT).
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19. The memory cell as recited in claim 18, wherein the PZT comprising the ferroelectric capacitor is of the form PbZrxTi1-xO3 with x ranging between 0.4 and 0.53.
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45. The memory module as recited in claim 18, wherein the PZT comprising the ferroelectric capacitor is of the form PbZrxTi1-xO3 with x ranging between 0.4 and 0.53.
- 20. A one transistor/one capacitor (1T/1C) memory cell array, wherein each of the 1T/1C memory cells comprises an edge defined ferroelectric capacitor operatively coupled to the gate electrode of a charge amplifier transistor by a polysilicon interconnect, wherein the edge defined ferroelectric capacitor is in a stacked alignment with an active gate oxide channel region of the transistor.
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26. A memory cell array, comprising:
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a plurality of memory cells organized as an array of rows and columns, at least one of the memory cells being a nonvolatile memory cell comprising;
a charge transistor comprising a gate opposing a channel region coupling source and drain regions;
a digitline coupled to the drain region;
a source line coupled to the source region, an edge defined ferroelectric capacitor coupled to the gate by a polysilicon interconnect;
a wordline coupled to the edge defined ferroelectric capacitor; and
a sense amplifier coupled to the digitline of the at least one memory cell, wherein the edge defined ferroelectric capacitor is in a stacked alignment with an active gate oxide channel region of the transistor. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34)
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35. A processor based system, comprising:
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a processor; and
a memory cell array coupled to the processor, the memory cell array including a plurality) of memory cells organized as an array of rows and columns, at least one of the memory cells being a non-volatile memory cell comprising;
a charge amplifier comprising a gate opposing a channel region coupling source and drain regions;
a digitline coupled to the drain region;
a source line coupled to the source region;
an edge defined ferroelectric capacitor coupled to the gate by a polysilicon interconnect;
a wordline coupled to the edge defined ferroelectric capacitor; and
a sense amplifier coupled to the digitline of the at least one memory cell, wherein the edge defined ferroelectric capacitor is in a stacked alignment with an active gate oxide channel region of the charge amplifier. - View Dependent Claims (36, 37, 38, 39, 40)
data is written into the ferroelectric capacitor when the wordline and the source line are both asserted; and
data is read out of the memory cell when the wordline, the digitline and the source line are asserted.
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38. The processor based system as recited in claim 35, wherein ferroelectric capacitor comprises an edge defined ferroelectric capacitor.
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39. The processor based system as recited in claim 35, wherein the ferroelectric capacitor comprises a dielectric layer of lead zirconate titanate (PZT).
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40. The processor based system as recited in claim 39, wherein the PZT comprising the ferroelectric capacitor is of the form PbZrxTi1-xO3 with x ranging between 0.4 and 0.53.
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41. A memory module, comprising:
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a substrate;
a plurality of memory chips mounted on the substrate, wherein one or more of the memory chips comprise a memory cell array fabricated on a semiconductor chip and communicating with a processor, said memory cell array comprising at least one non-volatile memory cell comprising an edge defined ferroelectric capacitor operatively coupled to the gate of a charge amplifier by a polysilicon interconnect, wherein the edge defined ferroelectric capacitor is in a stacked alignment with an active gate oxide channel region of the charge amplifier. - View Dependent Claims (42, 43, 44, 46)
the junction formed at the gate has an intrinsic capacitance; and
the capacitance of the ferroelectric capacitor is based on the magnitude of the intrinsic capacitance.
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43. The memory module as recited in claim 41, wherein:
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the junction formed at the gate has an intrinsic capacitance; and
the physical size of the ferroelectric capacitor is based on the magnitude of the intrinsic capacitance.
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44. The memory module as recited in claim 41, wherein the ferroelectric capacitor comprises a dielectric layer of lead zirconate titanate (PZT).
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46. The memory module as recited in claim 41, wherein the non-volatile memory cell comprises:
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the charge amplifier, which comprises the gate disposed adjacent to a channel region coupling source and drain regions;
a digitline coupled to drain region;
a source line coupled to the source region, the ferroelectric capacitor coupled to the gate; and
a wordline coupled to the ferroelectric capacitor.
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47. A method for reading information from a one transistor/one capacitor (1T/1C) memory cell having a charge amplifier including a gate disposed adjacent to a channel region coupling source and drain regions, a digitline coupled to the drain region, a source line coupled to the source region, an edge defined ferroelectric capacitor coupled to the gate by a polysilicon interconnect, and a wordline coupled to the ferroelectric capacitor, wherein the edge defined ferroelectric capacitor is in a stacked alignment with an active gate oxide channel region of the charge amplifier, the method comprising:
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grounding the source line;
asserting the wordline and digitline;
amplifying the charge on the edge defined ferroelectric capacitor; and
determining the resultant charge on the digitline. - View Dependent Claims (48, 49)
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50. A method for writing information to a one transistor/one capacitor (1T/1C) memory cell having a charge amplifier including a gate disposed adjacent to a channel region coupling source and drain regions, a digitline coupled to the drain region, a source line coupled to the source region, an edge defined ferroelectric capacitor coupled to the gate by a polysilicon interconnect, and a wordline coupled to the edge defined ferroelectric capacitor, wherein the edge defined ferroelectric capacitor is in a stacked alignment with an active gate oxide channel region of the charge amplifier, the method comprising:
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asserting the source line; and
asserting the wordline to thereby apply a potential greater than the coercive voltage of the edge defined ferroelectric capacitor across the edge defined ferroelectric capacitor and the charge amplifier. - View Dependent Claims (51)
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52. A logic element, comprising:
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N+1 source/drain regions;
N channels, each channel coupling adjacent ones of the N+1 source/drain regions;
N gates disposed adjacent to the N channels;
N edge defined ferroelectric capacitors, each of the N edge defined ferroelectric capacitors coupled to a respective one of the N gates by a polysilicon interconnect;
a digitline coupled to an end one of the N+1 source/drain regions; and
a source line coupled to the other end one of the N+1 source/drain regions wherein each of the N edge defined ferroelectric capacitors is in a stacked alignment with an active gate oxide channel region of a respective one of the N gates. - View Dependent Claims (53, 54, 55)
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Specification