Abstract: Ferroelectric capacitor structures for integrated decoupling capacitors and the like. The ferroelectric capacitor structure includes two or more ferroelectric capacitors connected in series with one another between voltage nodes. The series connection of the ferroelectric capacitors reduces the applied voltage across each, enabling the use of rough ferroelectric dielectric material, such as PZT deposited by MOCVD. Matched construction of the series-connected capacitors, as well as uniform polarity of the applied voltage across each, is beneficial in reducing the maximum voltage across any one of the capacitors, reducing the vulnerability to dielectric breakdown.

Abstract: Non-volatile latch circuits, such as in memory cells and flip-flops, that are constructed for reliability screening. The non-volatile latch circuits each include ferroelectric capacitors coupled to storage nodes, for example at the outputs of cross-coupled inverters. Separate plate lines are connected to the ferroelectric capacitors of the complementary storage nodes. A time-zero test of the latch stability margin is performed by setting a logic state at the storage nodes, then programming the state into the ferroelectric capacitors by polarization. After power-down, the plate lines are biased with a differential voltage relative to one another, and the latch is then powered up to attempt recall of the programmed state. The differential voltage disturbs the recall, and provides a measure of the cell margin and its later-life reliability.

Abstract: An FRAM device can comprise a sense amplifier and at least a first bitcell. The first bitcell can have a bit line and a complimentary bit line that connects to the sense amplifier. A first precharge circuit responds to a first control signal during a test mode of operation to precharge the bit line with respect to a first voltage while a second precharge circuit responds to a second control signal (that is different from the first control signal) during the test mode of operation to precharge the complimentary bit line with respect to a test voltage that is different than the first voltage (such as, but not limited to, a test voltage of choice such as a voltage that is greater than ground but less than the first voltage).

Abstract: A self-timed sense amplifier read buffer pulls down a pre-charged high global bit line, which then feeds data into a tri state write back buffer that is connected directly to the bit line. The bit line provides charge to a ferroelectric capacitor to write a logical “one” or “zero” while by-passing an isolator switch disposed between the sense amplifier and the ferroelectric capacitor. Because the sense amplifier uses grounded bit line sensing, the read buffer will not start pulling down the global bit line until after the sense amplifier signal amplification, which makes the timing of the control signal for this read buffer non-critical. The write-back buffer enable timing is also self-timed off of the sense amplifier. Therefore, the read data write-back to a ferroelectric memory cell is locally controlled and begins quickly after reading data from the ferroelectric memory cell, thereby allowing a quick cycle time.

Abstract: A ferroelectric memory device includes a shunt switch configured to short both sides of the ferroelectric capacitor of the ferroelectric memory device. The shunt switch is configured therefore to remove excess charge from around the ferroelectric capacitor prior to or after reading data from the ferroelectric capacitor. By one approach, the shunt switch is connected to operate in reaction to signals from the same line that controls accessing the ferroelectric capacitor. So configured, the high performance cycle time of the ferroelectric memory device is reduced by eliminating delays used to otherwise drain excess charge from around the ferroelectric capacitor, for example by applying a precharge voltage. The shunt switch also improves reliability of the ferroelectric memory device by ensuring that excess charge does not affect the reading of the ferroelectric capacitor during a read cycle.

Abstract: An FRAM device can comprise a sense amplifier, at least a first bitcell, a first control line, and a second control line. The first bitcell can have a bit line that connects to the sense amplifier via a first isolator and a complimentary bit line that connects to the sense amplifier via a second isolator that is different from the first isolator. The first control line can connect to and control the aforementioned first isolator. And the second control line can connect to and control the second isolator such that the second isolator is independently controlled with respect to the first isolator to facilitate testing the device.

Abstract: A ferroelectric apparatus includes a circuit having a first capacitor electrically coupled to a plate line via a top terminal connection of the first ferroelectric capacitor and to a storage node via a bottom terminal connection of the first ferroelectric capacitor. The circuit also includes a second ferroelectric capacitor electrically coupled to a second plate line via a second bottom terminal connection of the second ferroelectric capacitor and to the storage node via a second top terminal connection of the second ferroelectric capacitor.

Abstract: Non-volatile latch circuits, such as in memory cells and flip-flops, that are constructed for reliability screening. The non-volatile latch circuits each include ferroelectric capacitors coupled to storage nodes, for example at the outputs of cross-coupled inverters. Separate plate lines are connected to the ferroelectric capacitors of the complementary storage nodes. A time-zero test of the latch stability margin is performed by setting a logic state at the storage nodes, then programming the state into the ferroelectric capacitors by polarization. After power-down, the plate lines are biased with a differential voltage relative to one another, and the latch is then powered up to attempt recall of the programmed state. The differential voltage disturbs the recall, and provides a measure of the cell margin and its later-life reliability.