133 results about "Fowler nordheim" patented technology

A non-volatile memory (NVM) cell and array includes a control capacitor, tunneling capacitor, CMOS inverter and output circuit. The CMOS inverter includes PMOS and NMOS inverter transistors. The control capacitor, tunneling capacitor and PMOS and NMOS inverter transistors share a common floating gate, which is programmed/erased by Fowler-Nordheim tunneling. The output circuit includes PMOS and NMOS select transistors. The PMOS inverter and select transistors share a common source/drain region. Similarly, the NMOS inverter and select transistors share a common source/drain region. This configuration minimizes the required layout area of the non-volatile memory cell and allows design of arrays with smaller footprints. Alternately, the tunneling capacitor may be excluded, further reducing the required layout area of the NVM cell. In this case, the NMOS inverter transistor functions as a tunneling capacitor for programming and erasing the cell, and the PMOS inverter transistor functions as a tunneling capacitor for erasing the cell.

A memory array contains memory cells designed to be erased using Fowler-Nordheim ("FN") tunneling through the channel area, and programmed using either channel hot electron injection ("CHE") or channel-initiated secondary electron injection ("CISEI"). To reduce disturbance of the floating gate potential of unselected memory cells during programming operations and read operations, the unselected word lines are brought to a negative potential rather than ground potential. To reduce disturbance of the floating gate potential of unselected memory cells during FN erase operations, the unselected word lines are brought to a positive potential rather than ground potential.

A NOR flash nonvolatile memory device provides the memory cell size and a low current program process of a NAND flash nonvolatile memory device and the fast, asynchronous random access of a NOR flash nonvolatile memory device. The NOR flash nonvolatile memory device has an array of NOR flash nonvolatile memory circuits. Each NOR flash nonvolatile memory circuit includes a plurality of charge retaining transistors serially connected in a NAND string. A drain of a topmost charge retaining transistor is connected to a bit line associated with the serially connected charge retaining transistors and a source of a bottommost charge retaining transistor is connected to a source line associated with the charge retaining transistors. Each control gate of the charge retaining transistors on each row is commonly connected to a word line. The charge retaining transistors are programmed and erased with a Fowler-Nordheim tunneling process.

A non-volatile memory array includes memory cells connected in a common source arrangement and formed in columns of isolated well regions so that Fowler-Nordheim tunneling is used for both write and erase operations of the memory cells. The memory arrays can be formed as NOR arrays or NAND arrays. In one embodiment, the memory array of the present invention is formed as a byte alterable EEPROM with parallel access. In another embodiment, an insulated gate bipolar transistor (IGBT) is coupled to the memory cells to increase the cell read current of the memory array. When the memory array incorporates IGBTs on the bitlines, the cell read current becomes independent of the wordline voltages. Thus, the memory array of the present invention can be operated at low voltages. The use of IGBTs in the memory array of the present invention enables formation of embedded non-volatile memories in low-voltage digital integrated circuits.

A single polycrystalline silicon floating gate nonvolatile memory cell has a MOS capacitor and a storage MOS transistor fabricated with dimensions that allow fabrication using current low voltage logic integrated circuit process. The MOS capacitor has a first plate connected to a gate of the storage MOS transistor to form a floating gate node. The physical size of the MOS capacitor is relatively large (approximately 10 time greater) when compared to a physical size of the storage MOS transistor to establish a large coupling ratio (approximately 90% between the second plate of the MOS capacitor and the floating gate node. When a voltage is applied to the second plate of the MOS capacitor and a voltage applied to the source region or drain region of the MOS transistor establishes a voltage field within the gate oxide of the MOS transistor such that Fowler-Nordheim edge tunnel is initiated.

To control the problem of program and erase disturb in flash memory arrays having multiple sectors of cells grouped in each isolation wells of the flash memory array, a refresh procedure is used that involves two readings of each of the cells in a “refresh area” of a group under different read timing conditions, with other read conditions being constant or varied as desired. Cells that yield the same result in both reads are not excessively disturbed and need not be reprogrammed. However, cells that read differently may be excessively disturbed and should be reprogrammed. The refresh procedure is particularly suitable for memory arrays with small sector size and many sectors per group. The memory arrays preferably incorporate memory cells that use hot electron programming and Fowler-Nordheim erase.

An erase method where a corner portion on which an electric field concentrates locally is provided on the memory gate electrode, and charges in the memory gate electrode are injected into a charge trap film in a gate dielectric with Fowler-Nordheim tunneling operation is used. Since current consumption at the time of erase can be reduced by the Fowler-Nordheim tunneling, a power supply circuit area of a memory module can be reduced. Since write disturb resistance can be improved, a memory array area can be reduced by adopting a simpler memory array configuration. Owing to both the effects, an area of the memory module can be largely reduced, so that manufacturing cost can be reduced. Further, since charge injection centers of write and erase coincide with each other, so that (program and erase) endurance is improved.

A nonvolatile memory cell having a floating gate for the storage of charges thereon has a control gate and a separate erase gate. The cell is programmed by hot channel electron injection and is erased by poly to poly Fowler-Nordheim tunneling. A method for making an array of unidirectional cells in a planar substrate, as well as an array of bidirectional cells in a substrate having a trench, is disclosed. An array of such cells and a method of making such an array is also disclosed.

Provided is a method for operating a NOR-type flash memory device using SONOS cells. The SONOS cells are selectively programmed using channel hot electron injection and erased using Fowler-Nordheim tunneling and hot hole injection. When the SONOS cells are programmed, a voltage within a range of 8V-12V is applied to a selected word line and a voltage within a range of 3V-6V is applied to a selected bit line. When the SONOS cells are erased, the selected word line is ground and a voltage within a range of 13V-18V is applied to a substrate. Alternatively, a voltage of about −8V is applied to the selected word line, a voltage of about 6V is applied to the substrate, and a bit line and a source line float.

The charge-trapping layer comprises two strips above the source and drain junctions. The thicknesses of the charge-trapping layer and the gate dielectric are chosen to facilitate Fowler-Nordheim-tunnelling of electrons into the strips during an erasure process. Programming is performed by injection of hot holes into the strips individually for two-bit storage.

A nonvolatile memory array has a single transistor flash memory cell and a two transistor EEPROM memory cell which maybe integrated on the same substrate. The nonvolatile memory cell has a floating gate with a low coupling coefficient to permit a smaller memory cell. The floating gate placed over a tunneling insulation layer, the floating gate is aligned with edges of the source region and the drain region and having a width defined by a width of the edges of the source the drain. The floating gate and control gate have a relatively small coupling ratio of less than 50% to allow scaling of the nonvolatile memory cells. The nonvolatile memory cells are programmed with channel hot electron programming and erased with Fowler Nordheim tunneling at relatively high voltages.

In accordance with the present invention, a memory cell includes a non-volatile device and a SRAM cell. The SRAM cell includes first and second MOS transistors. The non-volatile device is a load to the SRAM cell. The memory cell may be adapted to operate differentially if a second SRAM cell and a second non-volatile device is disposed therein. If so adapted, the SRAM cells and/or the non-volatile devices when programmed store and supply complementary data. The non-volatile devices are erased prior to being programmed. Programming of the non-volatile devices may be done via hot-electron injection or Fowler-Nordheim tunneling. When a power failure occurs, the data stored in the SRAM are loaded in the non-volatile devices. After the power is restored, the data stored in the non-volatile devices are restored in the SRAM cells. The differential reading and wring of data reduces over-erase of the non-volatile devices.

Current Voltage and Capacitance Voltage (IV and CV) measurements are critical in measurement of properties of electronic materials especially semiconductors. A semiconductor testing device to accomplish IV and CV measurement supports a semiconductor wafer and provides a probe for contacting a surface on the wafer under control of an atomic Force Microscope or similar probing device for positioning the probe to a desired measurement point on the wafer surface. Detection of contact by the probe on the surface is accomplished and test voltage is supplied to the semiconductor wafer. A first circuit for measuring capacitance sensed by the probe based on the test voltage and a complimentary circuit for measuring Fowler Nordheim current sensed by the probe based on the test voltage are employed with the probe allowing the calculation of characteristics of the semiconductor wafer based on the measured capacitance and Fowler Nordheim current.

The present invention provides a non-volatile memory cell structure suitable for the flash memory cell and EEPROM cell (electrically erasable programmable read only memory cell) to perform the byte programming and byte erase operations. In the programming operation, a higher negative voltage applied to the drain region, such that the hot hole is generated to induce the hot electron into the floating gate through the tunneling oxide layer in the lateral electrical field. In addition, the gate voltage is around the threshold voltage, which dependent on the integration circuit device design. Furthermore, the non-volatile memory cell utilized the channel Fowler-Nordheim tunneling for erasing operation. In order to perform the byte erasing operation, the drain junction used as an inhibition switch. Thus, the unselected cell in the same word line is inhibited by biasing the drain to ground. Therefore, the word lines of unselected cells are ground.

A Trap Read Only Memory (TROM) architecture employs a NAND-type array structure configured as a read-only memory that is programmed only one time. The memory cells in the array comprise a gate terminal, a first channel terminal (source/drain), a second channel terminal (drain/source) and a channel region between the first and second channel terminals. A charge trapping structure, such as a layer of silicon nitride, is formed over the channel region. A tunneling dielectric is placed between the channel region and the charge trapping structure, and a blocking dielectric is placed between the charge trapping structure and the gate terminal. An E-field assisted (Fowler-Nordheim FN) tunneling program algorithm is applied.

A charge trapping memory device in which a field induced inversion layer is used to replace the source and drain implants. The memory cell are adapted to store two bits, one on the left side and one on the right side of the charge trapping structure. A positive threshold voltage erase state is induced using negative gate voltage Fowler Nordheim FN tunneling which establishes a charge balance condition at a positive voltage. A low current, source side, hot electron injection programming method is used.

A low-voltage nonvolatile memory array includes a cell well of a first conductivity type formed in a substrate; columns of buried bit lines of a second conductivity type formed within the cell well, wherein columns of the buried bit lines are isolated from each other and each is further divided into of sub-bit line segments with deeply doped source wells of the first conductivity type connected to the cell well; a plurality of memory cell blocks serially arranged over one of the columns of buried bit lines, wherein a memory cell block corresponds to a sub-bit line segment, and each memory cell block includes at least one memory transistor having a stacked gate, source, and drain; and a local bit line overlying the memory cell blocks and electrically connected to the drain of the memory transistor via a contact plug short-circuiting the drain and the subjacent buried bit line.