Abstract: Methods and apparatus for performing formal verification of a system defined by a set of automata are useful in facilitating computing efficiencies during the verification of an incremental system design. The various embodiments permit computing efficiencies by saving information generated during a verification of the system for use in subsequent verification runs. The saved information includes calculation results pertaining to instances or elements of the system that do not require modification for the next subsequent verification.

Abstract: Methods of sensing the programmed state of a floating-gate memory cell utilize a reference current applied to an input node of a sensing device during sensing, thus compensating for residual current and improving immunity to erroneous indications of an erased state.

Abstract: Depletion-mode ferroelectric transistors are adapted for use as non-volatile memory cells. Various embodiments are described having a diode interposed between the bit line and a source/drain region of the transistor for added margin against read disturb. Various additional embodiments are described having an array architecture such that two memory cells sharing the same bit line also share the same program line. Using this configuration, non-selected cells are readily supplied with gate/source voltages sufficient to maintain the cells in a deactivated state during read and write operations on selected cells.

Abstract: Floating-gate memory cells having a trench source-line contact are suited for increased packing densities without a need for low-resistance ground straps placed at regular intervals across a memory array. Such floating-gate memory cells have their drain regions and source regions formed in a first semiconductor region having a first conductivity type. This first semiconductor region is separated from the underlying substrate by an interposing second semiconductor region having a second conductivity type different from the first conductivity type. The source regions of the memory cells are coupled to the second semiconductor region as a common source line. Such memory cells can be programmed, read and erased by applying various potential levels to their control gates, their drain regions, the first semiconductor region, and the second semiconductor region.

Abstract: Floating-gate memory cells having a trench source-line contact are suited for increased packing densities without a need for low-resistance ground straps placed at regular intervals across a memory array. Such floating-gate memory cells have their drain regions and source regions formed in a first semiconductor region having a first conductivity type. This first semiconductor region is separated from the underlying substrate by an interposing second semiconductor region having a second conductivity type different from the first conductivity type. The source regions of the memory cells are coupled to the second semiconductor region as a common source line. Such memory cells can be programmed, read and erased by applying various potential levels to their control gates, their drain regions, the first semiconductor region, and the second semiconductor region.

Abstract: Single-ended sensing devices for sensing a programmed state of a floating-gate memory cell are adapted for use in low-voltage memory devices. The sensing device has an input node selectively coupled to the memory cell. The sensing device includes a precharging path for applying a precharge potential to the input node of the sensing device for precharging bit lines prior to sensing the programmed state of the memory cell, and a reference current path for applying a reference current to the input node of the sensing device. The sensing device still further includes a sense inverter having an input coupled to the input node of the sensing device and an output for providing an output signal indicative of the programmed state of the memory cell. The reference current is applied to the input node of the sensing device during sensing of the programmed state of the memory cell.

Abstract: Memory devices having multiple bit line column redundancy are suited for high-performance memory devices, with particular reference to synchronous non-volatile memory devices. Such memory devices include blocks of memory cells arranged in columns with each column of memory cells coupled to a local bit line. Such memory devices further include global bit lines having multiple local bit lines selectively coupled to each global bit line, with each global bit line extending to local bit lines in each memory block of a memory sector. Repair of one or more defective columns of memory cells within a sector is effected by providing a redundant grouping of memory cells having a redundant sense amplifier, global bit lines and local bit lines. Each grouping of memory cells contains four or more columns of memory cells. A defect in one column of memory cells results in replacement of four or more columns of memory cells.

Abstract: Memory devices having multiple bit line column redundancy are suited for high-performance memory devices, with particular reference to synchronous non-volatile memory devices. Such memory devices include blocks of memory cells arranged in columns with each column of memory cells coupled to a local bit line. Such memory devices further include global bit lines having multiple local bit lines selectively coupled to each global bit line, with each global bit line extending to local bit lines in each memory block of a memory sector. Repair of one or more defective columns of memory cells within a sector is effected by providing a redundant grouping of memory cells having a redundant sense amplifier, global bit lines and local bit lines. Each grouping of memory cells contains four or more columns of memory cells. A defect in one column of memory cells results in replacement of four or more columns of memory cells.

Abstract: Memory devices including blocks of memory cells arranged in columns, with each column of memory cells coupled to a main bit line, are organized for high-speed access and tight packing. Such memory devices include sector bit lines having multiple main bit lines selectively coupled to each sector bit line, with each sector bit line extending to main bit lines in each memory block of a memory sector. Sector bit lines are coupled to sensing devices and the output of each sensing device is selectively coupled to a global bit line, with each global bit line selectively coupled to more than one sensing device. The global bit lines are multiplexed and input to helper flip-flops for output to the data output register of the memory device. Various embodiments include non-volatile, and, particularly, synchronous non-volatile memory devices having multiple banks containing multiple sectors of such memory blocks.

Abstract: Bi-state ferroelectric-MOS (FMOS) capacitors are adapted for use in memory cells of a memory device. Bi-state ferroelectric memory cells have a bottom plate of a capacitor coupled to a first source/drain region of a pass transistor, a gate of the pass transistor coupled to a word line, and a second source/drain region of the pass transistor coupled to a bit line. A plate line is coupled to the top plate of the capacitor to facilitate programming of the polarization state of a ferroelectric portion of the capacitor. The polarization state of the ferroelectric portion of the capacitor causes a depletion or accumulation of electrons in the bottom plate of the capacitor, thus altering its capacitance value. The resulting capacitance value may be sensed without causing a polarization reversal of the ferroelectric portion of the capacitor. Accordingly, bi-state ferroelectric memory cells of the various embodiments function as non-volatile memory cells.

Abstract: Memory chips containing multiple-bank memory devices are arranged to be mounted in a memory package with the major axis of the memory chip aligned substantially parallel with the major axis of its memory package. Memory devices of various embodiments contain banks of non-volatile flash memory cells and have access commands synchronized to a system clock. Data chip bond pads for coupling to data pins of a memory package are located in a first quadrant of the memory chip. Address chip bond pads for coupling to address pins of a memory package are located in an opposite quadrant of the memory chip.

Abstract: Memory devices having redundancy selection circuitry are adapted to introduce test input signals into the redundancy selection path. The memory devices include a redundancy selection circuit having a latch for latching an incoming redundancy match signal. The latch includes a pair of reverse-coupled inverters. The latch is further coupled to receive one or more test input signals. The latch is responsive to one or more control signals to selectively generate the latched match signal from the incoming redundancy match signal or one of the test input signals. Such latch circuits are useful for controlling selection of a redundant element in a memory device during testing without significantly impacting the speed path of the redundancy selection circuitry during normal operation of the memory device.

Abstract: Semiconductor container capacitor structures having a diffusion barrier layer to reduce damage of the bottom cell plate and any underlying transistor from species diffused through the surrounding insulating material are adapted for use in high-density memory arrays. The diffusion barrier layer can protect the bottom cell plate, any underlying access transistor and even the surface of the surrounding insulating layer during processing including pre-treatment, formation and post-treatment of the capacitor dielectric layer. The diffusion barrier layer inhibits or impedes diffusion of species that may cause damage to the bottom plate or an underlying transistor, such as oxygen-containing species, hydrogen-containing species and/or other undesirable species. The diffusion barrier layer is formed separate from the capacitor dielectric layer. This facilitates thinning of the dielectric layer as the dielectric layer need not provide such diffusion protection.

Abstract: Floating-gate memory cells having a control gate for coupling to a word line, a floating gate, a first source/drain region for coupling to a bit line, and a floating second source/drain region are adapted for use in flash memory devices. Such floating-gate memory cells eliminate the need to provide electrical contact to the second source/drain region, thus simplifying the fabrication process and array architecture. The floating-gate memory cells may be programmed using band-to-band tunneling. The floating-gate memory cells may be read using capacitance sensing or forward current sensing techniques.

Abstract: Bi-state ferroelectric-MOS (FMOS) capacitors are adapted for use in memory cells of a memory device. Bi-state ferroelectric memory cells have a bottom plate of a capacitor coupled to a first source/drain region of a pass transistor, a gate of the pass transistor coupled to a word line, and a second source/drain region of the pass transistor coupled to a bit line. A plate line is coupled to the top plate of the capacitor to facilitate programming of the polarization state of a ferroelectric portion of the capacitor. The polarization state of the ferroelectric portion of the capacitor causes a depletion or accumulation of electrons in the bottom plate of the capacitor, thus altering its capacitance value. The resulting capacitance value may be sensed without causing a polarization reversal of the ferroelectric portion of the capacitor. Accordingly, bi-state ferroelectric memory cells of the various embodiments function as non-volatile memory cells.

Abstract: Depletion-mode ferroelectric transistors are adapted for use as non-volatile memory cells. Various embodiments are described having a diode interposed between the bit line and a source/drain region of the transistor for added margin against read disturb. Various additional embodiments are described having an array architecture such that two memory cells sharing the same bit line also share the same program line. Using this configuration, non-selected cells are readily supplied with gate/source voltages sufficient to maintain the cells in a deactivated state during read and write operations on selected cells.

Abstract: Memory devices having redundancy selection circuitry are suited for high-performance memory devices, with particular reference to synchronous non-volatile memory devices capable of concurrent read and write operations. Such memory devices include a redundancy comparator for comparing address signals applied to the memory device to known defective address, and for selecting redundant elements if a match is identified. A redundancy comparator includes at least one redundancy compare latch circuit, each redundancy compare latch circuit having a mapping latch circuit, a read address compare circuit coupled to the mapping latch circuit, and a write address compare circuit coupled to the mapping latch circuit. The read address compare circuit and the write address compare circuit thus share the same mapping latch circuit. Such circuits are capable of simultaneously comparing a read address signal and a write address signal, thus facilitating concurrent read and write operations.

Abstract: Memory devices having multiple bit line column redundancy are suited for high-performance memory devices, with particular reference synchronous non-volatile memory devices. Such memory devices include bloc of memory cells arranged in columns with each column of memory cells coupled to a local line. Such memory devices further include global bit lines having multiple local bit lines selectively coupled to each global bit line, with each global bit line extending to local bit lines in each memory block of a memory sector. Global bit lines are coupled to sensing devices generally in pairs. Repair of one or more defective columns of memory cells within a sector is effected by providing a redundant grouping of memory cells having a redundant sense amplifier, global bit lines and local bit lines. Each grouping of memory cells contains four or more columns of memory cells.

Abstract: Memory chips containing multiple-bank memory devices are arranged to be mounted in a memory package with the major axis of the memory chip aligned substantially parallel with the major axis of its memory package. Memory devices of various embodiments contain banks of non-volatile flash memory cells and have access commands synchronized to a system clock. Data chip bond pads for coupling to data pins of a memory package are located in a first quadrant of the memory chip. Address chip bond pads for coupling to address pins of a memory package are located in an opposite quadrant of the memory chip.

Abstract: Memory devices having redundancy selection circuitry are adapted to introduce test input signals into the redundancy selection path. The memory devices include a redundancy selection circuit having a latch for latching an incoming redundancy match signal. The latch includes a pair of reverse-coupled inverters. The latch is further coupled to receive one or more test input signals. The latch is responsive to one or more control signals to selectively generate the latched match signal from the incoming redundancy match signal or one of the test input signals. When the latched match signal is generated from the incoming redundancy match signal, the logic level of the latched match signal is independent of the logic level of any of the test input signals. When the latched match signal is generated from one of the test input signals, the logic level of the latched match signal is independent of the logic level of the incoming redundancy match signal.