US6337805B1
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Discrete devices including EAPROM transistor and NVRAM memory cell with edge defined ferroelectric capacitance, methods for operating same, and apparatuses including same
Assignee: Micron Technology Inc
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Filing: 1999-12-15
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Granted: 2002-01-08
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Expires: 2019-12-15
Abstract
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.
Inventors
- 👤 Leonard Forbes
- 👤 Wendell P. Noble
- 👤 Kie Y. Ahn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 08:53
CPC Classifications
G; G11; G11C; G11C11/00; G11C11/005; G11C11/21; G11C11/22; G11C11/34; G11C11/40; G11C11/401; G11C11/403; G11C11/404; H; H10; H10B; H10B53/00; G11C11/223
Claims Analysis
Total Claims: 65
Claim 1
Independent Claim
49 words
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.
Claim 2
Dependent Claim
49 words
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.
Claim 3
Dependent Claim
30 words
The memory cell as recited in claim 1 , wherein the ferroelectric capacitor has a surface area which is a predetermined percentage of the surface area of the gate electrode.
Claim 4
Dependent Claim
19 words
The memory cell as recited in claim 1 , wherein the ferroelectric capacitor comprises an edge defined ferroelectric capacitor.
Claim 5
Dependent Claim
18 words
The memory cell as recited in claim 1 , wherein the charge amplifier transistor comprises a CMOS transistor.
Claim 6
Dependent Claim
87 words
A memory cell comprising: 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.
Claim 7
Dependent Claim
87 words
A memory cell comprising: 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.
Claim 8
Dependent Claim
16 words
The memory cell as recited in claim 5 , wherein the charge amplifier comprises a transistor.
Claim 9
Dependent Claim
17 words
The memory cell as recited in claim 5 , wherein the charge amplifier comprises a CMOS transistor.
Claim 10
Dependent Claim
36 words
The memory cell as recited in claim 5 , wherein: 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.
Claim 11
Dependent Claim
37 words
The memory cell as recited in claim 5 , wherein: 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.
Claim 12
Dependent Claim
30 words
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.
Claim 13
Dependent Claim
92 words
A 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, 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.
Claim 14
Dependent Claim
92 words
A 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, 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.
Claim 15
Dependent Claim
17 words
The memory cell as recited in claim 11 , wherein the charge amplifier is a CMOS transistor.
Claim 16
Dependent Claim
32 words
The memory cell as recited in claim 11 , wherein the ferroelectric capacitor has a surface area which is a predetermined percentage of surface area of the gate of the charge amplifier.
Claim 17
Dependent Claim
36 words
The memory cell as recited in claim 11 , wherein: 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.
Claim 18
Dependent Claim
37 words
The memory cell as recited in claim 11 , wherein: 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.
Claim 19
Dependent Claim
19 words
The memory cell as recited in claim 11 , wherein the ferroelectric capacitor is an edge defined ferroelectric capacitor.
Claim 20
Dependent Claim
24 words
The memory cell as recited in claim 16 , wherein the edge defined ferroelectric capacitor comprises a dielectric layer of lead zirconate titanate (PZT).
Claim 21
Dependent Claim
22 words
The memory cell as recited in claim 11 , wherein the ferroelectric capacitor comprises a dielectric layer of lead zirconate titanate (PZT).
Claim 22
Dependent Claim
33 words
The memory cell as recited in claim 18 , wherein the PZT comprising the ferroelectric capacitor is of the form PbZr x Ti 1-x O 3 with x ranging between 0.4 and 0.53.
Claim 23
Dependent Claim
57 words
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.
Claim 24
Dependent Claim
57 words
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.
Claim 25
Dependent Claim
19 words
The memory cell array as recited in claim 20 , wherein the charge amplifier transistor comprises a CMOS transistor.
Claim 26
Dependent Claim
43 words
The memory cell array as recited in claim 20 , wherein the memory cell array comprises N rows by M columns of memory cells, and wherein the each of the M columns is defined by an associated digitline and an associated source line.
Claim 27
Dependent Claim
33 words
The memory cell array as recited in claim 20 , wherein the surface area of the ferroelectric capacitor is a predetermined percentage of the surface area of the gate of the charge amplifier.
Claim 28
Dependent Claim
20 words
The memory cell array as recited in claim 23 , wherein the ferroelectric capacitor is an edge defined ferroelectric capacitor.
Claim 29
Dependent Claim
24 words
The memory cell array as recited in claim 24 , wherein the edge defined ferroelectric capacitor comprises a dielectric layer of lead zirconate titanate.
Claim 30
Dependent Claim
119 words
A memory cell array, comprising: 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.
Claim 31
Dependent Claim
119 words
A memory cell array, comprising: 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.
Claim 32
Dependent Claim
29 words
The memory cell array as recited in claim 26 , wherein the ferroelectric capacitor has a surface area which is small relative to the surface area of the gate.
Claim 33
Dependent Claim
20 words
The memory cell array as recited in claim 26 , wherein the ferroelectric capacitor comprises an edge defined ferroelectric capacitor.
Claim 34
Dependent Claim
46 words
The memory cell array as recited in claim 26 , wherein data is written into the ferroelectric capacitor when the wordline and source line are asserted and data is read from the non-volatile memory cell when the wordline, the digitline and the source line are asserted.
Claim 35
Dependent Claim
20 words
The memory cell array as recited in claim 26 , wherein an asserted source line comprises a grounded source line.
Claim 36
Dependent Claim
29 words
The memory cell array as recited in claim 26 , wherein the charge amplifier amplifies the charge stored in the ferroelectric capacitor by at least one order of magnitude.
Claim 37
Dependent Claim
27 words
The memory cell array as recited in claim 26 , wherein the charge amplifier amplifies the charge stored in the ferroelectric capacitor by a predetermined gain factor.
Claim 38
Dependent Claim
17 words
The memory cell array as recited in claim 26 , wherein the charge amplifier comprises a transistor.
Claim 39
Dependent Claim
17 words
The memory cell array as recited in claim 33 , wherein the transistor comprises a CMOS transistor.
Claim 40
Dependent Claim
136 words
A processor based system, comprising: 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.
Claim 41
Dependent Claim
136 words
A processor based system, comprising: 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.
Claim 42
Dependent Claim
17 words
The processor based system as recited in claim 35 , wherein the charge amplifier comprises a transistor.
Claim 43
Dependent Claim
54 words
The processor based system as recited in claim 35 , wherein, under the control of the processor: 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.
Claim 44
Dependent Claim
19 words
The processor based system as recited in claim 35 , wherein ferroelectric capacitor comprises an edge defined ferroelectric capacitor.
Claim 45
Dependent Claim
23 words
The processor based system as recited in claim 35 , wherein the ferroelectric capacitor comprises a dielectric layer of lead zirconate titanate (PZT).
Claim 46
Dependent Claim
34 words
The processor based system as recited in claim 39 , wherein the PZT comprising the ferroelectric capacitor is of the form PbZr x Ti 1-x O 3 with x ranging between 0.4 and 0.53.
Claim 47
Dependent Claim
90 words
A memory module, comprising: 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.
Claim 48
Dependent Claim
90 words
A memory module, comprising: 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.
Claim 49
Dependent Claim
36 words
The memory module as recited in claim 41 , wherein: 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.
Claim 50
Dependent Claim
37 words
The memory module as recited in claim 41 , wherein: 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.
Claim 51
Dependent Claim
22 words
The memory module as recited in claim 41 , wherein the ferroelectric capacitor comprises a dielectric layer of lead zirconate titanate (PZT).
Claim 52
Dependent Claim
33 words
The memory module as recited in claim 18 , wherein the PZT comprising the ferroelectric capacitor is of the form PbZr x Ti 1-x O 3 with x ranging between 0.4 and 0.53.
Claim 53
Dependent Claim
62 words
The memory module as recited in claim 41 , wherein the non-volatile memory cell comprises: 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.
Claim 54
Independent Claim
118 words
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: 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.
Claim 55
Independent Claim
118 words
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: 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.
Claim 56
Dependent Claim
29 words
The method as recited in claim 47 , wherein the asserting step further comprises asserting the wordline at a voltage less than the coercive voltage of the ferroelectric capacitor.
Claim 57
Dependent Claim
26 words
The method as recited in claim 47 , wherein the asserting step further comprises asserting the digitline which has been charged to a predetermined voltage value.
Claim 58
Independent Claim
128 words
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: 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.
Claim 59
Independent Claim
128 words
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: 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.
Claim 60
Dependent Claim
18 words
The method as recited in claim 50 , wherein the asserted source line comprises a grounded source line.
Claim 61
Dependent Claim
109 words
A logic element, comprising: 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.
Claim 62
Dependent Claim
109 words
A logic element, comprising: 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.
Claim 63
Dependent Claim
23 words
The logic element as recited in claim 52 , wherein the logic element is operated by assertion of all of the N gates.
Claim 64
Dependent Claim
18 words
The logic element as recited in claim 52 , wherein the ferroelectric capacitors comprise edge defined ferroelectric capacitors.
Claim 65
Dependent Claim
47 words
The logic element as recited in claim 52 , further comprising N wordlines, each of the N wordlines coupled to a respective one of the N ferroelectric capacitors, wherein the logic element is operated by assertion of all of the N wordlines coupled to respective N gates.
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