US5579257A
Expired / Lapsed
US
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Method for reading and restoring data in a data storage element
Assignee: NXP USA Inc
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Filing: 1995-08-31
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Granted: 1996-11-26
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Expires: 2015-08-31
Abstract
Abstract A method for reading and restoring data in a FERAM (10) is provided. The FERAM (10) comprises a FET (11) and a ferroelectric capacitor (12). The FET (11) has a gate connected to a word line (14), a source coupled to a plate line (15) via the ferroelectric capacitor (12), and a drain connected to a bit line (16). The reading process begins by placing a predetermined amount of charge in a bit line capacitor (17), which in turn charges the ferroelectric capacitor (12) after the FET (11) is switched on, resulting in a voltage drop determined by data stored in the FERAM (10) at the bit line (16). A sense amplifier (18) adjusts the voltage at the bit line (16) accordingly to read data from the FERAM (10). Applying a voltage at the plate line (15) and switching the FET (11) off restore the data to the FERAM (10).
Inventors
- 👤 Jy-Der D. Tai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:03
CPC Classifications
G; G11; G11C; G11C11/00; G11C11/21; G11C11/22; G11C11/225; G11C11/2273; G11C11/221
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
208 words
A method for reading and restoring data in a data storage element, comprising the steps of: providing the data storage element having a switch and a capacitor with polarization retention, wherein the switch has a control electrode coupled for receiving control signals, a first current conducting electrode coupled via the capacitor with polarization retention for receiving restoration signals, and a second current conducting electrode coupled for transmitting data; providing data in the data storage element; placing the switch in a non-conductive state; applying a first restoration signal to the first current conducting electrode of the switch via the capacitor with polarization retention; applying a charging voltage to the second current conducting electrode of the switch; removing the charging voltage applied to the second current conducting electrode of the switch; placing the switch in a conductive state; applying a data value voltage to the second current conducting electrode of the switch in response to a voltage at the second current conducting electrode of the switch to read data from the data storage element; applying a second restoration signal to the first current conducting electrode of the switch via the capacitor with polarization retention; and placing the switch in the non-conductive state to restore data in the data storage element.
Claim 2
Independent Claim
208 words
A method for reading and restoring data in a data storage element, comprising the steps of: providing the data storage element having a switch and a capacitor with polarization retention, wherein the switch has a control electrode coupled for receiving control signals, a first current conducting electrode coupled via the capacitor with polarization retention for receiving restoration signals, and a second current conducting electrode coupled for transmitting data; providing data in the data storage element; placing the switch in a non-conductive state; applying a first restoration signal to the first current conducting electrode of the switch via the capacitor with polarization retention; applying a charging voltage to the second current conducting electrode of the switch; removing the charging voltage applied to the second current conducting electrode of the switch; placing the switch in a conductive state; applying a data value voltage to the second current conducting electrode of the switch in response to a voltage at the second current conducting electrode of the switch to read data from the data storage element; applying a second restoration signal to the first current conducting electrode of the switch via the capacitor with polarization retention; and placing the switch in the non-conductive state to restore data in the data storage element.
Claim 3
Dependent Claim
73 words
The method for reading and restoring data in a data storage element as claimed in claim 1, wherein the step of providing the data storage element further includes providing a word line coupled to the control electrode of the switch, a plate line coupled to the first current conducting electrode of the switch via the capacitor with polarization retention, and a bit line coupled to the second current conducting electrode of the switch.
Claim 4
Dependent Claim
98 words
The method for reading and restoring data in a data storage element as claimed in claim 1, wherein the step of providing the data storage element includes providing an n-channel insulated gate field effect transistor serving as the switch and providing a ferroelectric capacitor serving as the capacitor with polarization retention, wherein the n-channel insulated gate field effect transistor has a gate electrode serving as the control electrode of the switch, a source electrode serving as the first current conducting electrode of the switch, and a drain electrode serving as the second current conducting electrode of the switch.
Claim 5
Dependent Claim
109 words
The method for reading and restoring data in a data storage element as claimed in claim 1, wherein the step of providing data in the data storage element includes the steps of: applying the first restoration signal to the first current conducting electrode of the switch via the capacitor with polarization retention; applying a data storing voltage to the second current conducting electrode of the switch; placing the switch in a conductive state; applying the second restoration signal to the first current conducting electrode of the switch via the capacitor with polarization retention; and placing the switch in a non-conductive state to store data in the data storage element.
Claim 6
Dependent Claim
42 words
The method for reading and restoring data in a data storage element as claimed in claim 4, wherein the step of applying a data storing voltage includes applying a voltage determined by the data to be stored in the data storage element.
Claim 7
Dependent Claim
41 words
The method for reading and restoring data in a data storage element as claimed in claim 1, wherein the step of placing the switch in a non-conductive state includes applying a first control signal to the control electrode of the switch.
Claim 8
Dependent Claim
32 words
The method for reading and restoring data in a data storage element as claimed in claim 1, wherein the step of applying a second restoration signal includes applying the first restoration signal.
Claim 9
Independent Claim
165 words
A method for reading and restoring data in a ferroelectric memory cell, comprising the steps of: providing the ferroelectric memory cell having a word line, a plate line, a bit line, a field effect transistor, and a ferroelectric capacitor, wherein the field effect transistor has a gate electrode coupled to the word line, a source electrode coupled to the plate line via the ferroelectric capacitor, and a drain electrode coupled to the bit line; writing data into the ferroelectric memory cell; placing the field effect transistor in a non-conductive state; applying a first restoration signal to the plate line; charging the bit line; placing the field effect transistor in a conductive state; applying a data value voltage to the bit line in response to a potential at the bit line to read data from the ferroelectric memory cell; applying a second restoration signal to the plate line; and placing the field effect transistor in the non-conductive state to restore data in the ferroelectric memory cell.
Claim 10
Independent Claim
165 words
A method for reading and restoring data in a ferroelectric memory cell, comprising the steps of: providing the ferroelectric memory cell having a word line, a plate line, a bit line, a field effect transistor, and a ferroelectric capacitor, wherein the field effect transistor has a gate electrode coupled to the word line, a source electrode coupled to the plate line via the ferroelectric capacitor, and a drain electrode coupled to the bit line; writing data into the ferroelectric memory cell; placing the field effect transistor in a non-conductive state; applying a first restoration signal to the plate line; charging the bit line; placing the field effect transistor in a conductive state; applying a data value voltage to the bit line in response to a potential at the bit line to read data from the ferroelectric memory cell; applying a second restoration signal to the plate line; and placing the field effect transistor in the non-conductive state to restore data in the ferroelectric memory cell.
Claim 11
Dependent Claim
53 words
The method for reading and restoring data in a ferroelectric memory cell as claimed in claim 8, wherein the step of providing the ferroelectric memory cell includes providing an n-channel insulated gate field effect transistor serving as the field effect transistor, wherein the n-channel insulated gate field effect transistor has a threshold voltage.
Claim 12
Dependent Claim
51 words
The method for reading and restoring data in a ferroelectric memory cell as claimed in claim 9, wherein the step of placing the field effect transistor in a non-conductive state includes applying a voltage lower than the threshold voltage of the n-channel insulated gate field effect transistor to the word line.
Claim 13
Dependent Claim
35 words
The method for reading and restoring data in a ferroelectric memory cell as claimed in claim 8, wherein the step of applying a first restoration signal includes applying a ground voltage to the plate line.
Claim 14
Dependent Claim
35 words
The method for reading and restoring data in a ferroelectric memory cell as claimed in claim 8, wherein the step of applying a second restoration signal includes applying a supply voltage to the plate line.
Claim 15
Dependent Claim
47 words
The method for reading and restoring data in a ferroelectric memory cell as claimed in claim 8, wherein the step of charging the bit line includes the steps of: applying a charging voltage to the bit line; and removing the charging voltage applied to the bit line.
Claim 16
Dependent Claim
95 words
The method for reading and restoring data in a ferroelectric memory cell as claimed in claim 8, wherein the step of applying a data value voltage to the bit line in response to a potential at the bit line includes the steps of: providing a predetermined reference potential; applying a ground voltage to the bit line in response to the potential at the bit line lower than the predetermined reference potential; and applying a supply voltage to the bit line in response to the potential at the bit line higher than the predetermined reference potential.
Claim 17
Independent Claim
335 words
A method for reading and restoring data in a ferroelectric memory cell, comprising the steps of: providing the ferroelectric memory cell having a word line, a plate line, a bit line, a complementary bit line, a first field effect transistor, a second field effect transistor, a first ferroelectric capacitor, and a second ferroelectric capacitor, wherein a gate electrode of the first field effect transistor and a gate electrode of the second field effect transistor are coupled to the word line, a source electrode of the first field effect transistor and a source electrode of the second field effect transistor are coupled to the plate line via the first ferroelectric capacitor and the second ferroelectric capacitor, respectively, and a drain electrode of the first field effect transistor and a drain electrode of the second field effect transistor are coupled to the bit line and the complementary bit line, respectively; writing data into the ferroelectric memory cell; placing the first and second field effect transistors in a non-conductive state; applying a first restoration signal to the plate line; charging the bit line and the complementary bit line; placing the first and second field effect transistors in a conductive state; applying a first data value voltage to the bit line and applying a second data value voltage to the complementary bit line in response to a potential at the bit line higher than a potential at the complementary bit line to read a first logical value from the ferroelectric memory cell; applying the second data value voltage to the bit line and applying the first data value voltage to the complementary bit line in response to a potential at the bit line lower than a potential at the complementary bit line to read a second logical value complementary to the first logical value from the ferroelectric memory cell; applying a second restoration signal to the plate line; and placing the first and second field effect transistors in the non-conductive state to restore data in the ferroelectric memory cell.
Claim 18
Independent Claim
335 words
A method for reading and restoring data in a ferroelectric memory cell, comprising the steps of: providing the ferroelectric memory cell having a word line, a plate line, a bit line, a complementary bit line, a first field effect transistor, a second field effect transistor, a first ferroelectric capacitor, and a second ferroelectric capacitor, wherein a gate electrode of the first field effect transistor and a gate electrode of the second field effect transistor are coupled to the word line, a source electrode of the first field effect transistor and a source electrode of the second field effect transistor are coupled to the plate line via the first ferroelectric capacitor and the second ferroelectric capacitor, respectively, and a drain electrode of the first field effect transistor and a drain electrode of the second field effect transistor are coupled to the bit line and the complementary bit line, respectively; writing data into the ferroelectric memory cell; placing the first and second field effect transistors in a non-conductive state; applying a first restoration signal to the plate line; charging the bit line and the complementary bit line; placing the first and second field effect transistors in a conductive state; applying a first data value voltage to the bit line and applying a second data value voltage to the complementary bit line in response to a potential at the bit line higher than a potential at the complementary bit line to read a first logical value from the ferroelectric memory cell; applying the second data value voltage to the bit line and applying the first data value voltage to the complementary bit line in response to a potential at the bit line lower than a potential at the complementary bit line to read a second logical value complementary to the first logical value from the ferroelectric memory cell; applying a second restoration signal to the plate line; and placing the first and second field effect transistors in the non-conductive state to restore data in the ferroelectric memory cell.
Claim 19
Dependent Claim
70 words
The method for reading and restoring data in a ferroelectric memory cell as claimed in claim 15, wherein the step of providing the ferroelectric memory cell includes providing a first n-channel insulated gate field effect transistor having a first threshold voltage serving as the first field effect transistor and providing a second n-channel insulated gate field effect transistor having a second threshold voltage serving as the second field effect transistor.
Claim 20
Dependent Claim
49 words
The method for reading and restoring data in a ferroelectric memory cell as claimed in claim 16, wherein the step of placing the first and second field effect transistors in a conductive state includes applying a voltage higher than the first and second threshold voltages to the word line.
Claim 21
Dependent Claim
62 words
The method for reading and restoring data in a ferroelectric memory cell as claimed in claim 15, wherein the step of charging the bit line and the complementary bit line includes the steps of: applying a charging voltage to the bit line and the complementary bit line; and removing the charging voltage applied to the bit line and the complementary bit line.
Claim 22
Dependent Claim
39 words
The method for reading and restoring data in a ferroelectric memory cell as claimed in claim 15, wherein the step of applying a charging voltage includes applying a supply voltage to the bit line and the complementary bit line.
Claim 23
Dependent Claim
80 words
The method for reading and restoring data in a ferroelectric memory cell as claimed in claim 15, wherein the step of applying a first data value voltage to the bit line and applying a second data value voltage to the complementary bit line in response to a potential at the bit line higher than a potential at the complementary bit line includes applying a supply voltage to the bit line and applying a ground voltage to the complementary bit line.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-11-26 | 2000-05-27 | 2000-11-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-11-26 | 2004-05-27 | 2004-11-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-11-26 | 2008-05-27 | 2008-11-26 | $7700.00 | Window Closed / Lapsed |