Abstract: An abrupt drain junction and a graded source junction are fabricated using a common diffusion step, wherein the common diffusion step is used to create both the drain junction-and the source junction. The common diffusion step is accomplished while an oxide spacer is present over a gate stack, prior to the common diffusion step, resulting in faster source diffusion and a graded source junction, while the slower diffusion in the drain region results in an abrupt drain junction. The oxide spacer moves the drain junction further away from the gate stack to allow for greater cell densities.

Abstract: In one embodiment of the present invention, a method of forming semiconductor transistors includes: forming a gate electrode over but insulated from a semiconductor body region; forming off-set spacers along side-walls of the gate electrode; and after forming said off-set spacers, forming a source region and a drain region in the body region so that the extent of an overlap between the gate electrode and each of the source and drain regions is dependent on a thickness of the off-set spacers.

Abstract: In one embodiment of the present invention, a method of forming semiconductor transistors includes: forming a gate electrode over but insulated from a semiconductor body region; forming off-set spacers along side-walls of the gate electrode; and after forming said off-set spacers, forming a source region and a drain region in the body region so that the extent of an overlap between the gate electrode and each of the source and drain regions is dependent on a thickness of the off-set spacers.

Abstract: A flash EEPROM array having a double-diffused source junction that can be used for source side programming. The flash EEPROM array, when programmed from the source side exhibits fast programming rates. Additionally, source side programming of arrays having different physical characteristics (e.g. transistor cell channel length) exhibit tighter program rate distributions than for the same arrays in which drain side programming is used.

Abstract: A structure for a flash memory cell is described in which a triple well is formed with the memory cell residing in a P-well, which in turn is deposed in an N-well in a P-type substrate. The structure provides the ability to operate such memories with considerably lower operating potentials than prior art devices. A process for fabricating the flash memory cell is also described.

Abstract: A method of programming an electrically programmable memory cell which cell includes a transistor formed in a semiconductor substrate of first conductivity type having a surface a first well region of second conductivity type is disposed in the substrate adjacent the surface thereof. A second well region of first conductivity type is disposed in the first well region adjacent the surface. The transistor has a source region, a drain region, a floating gate, and a control gate. The method includes raising the control gate to a first selected potential no greater than 9.0 volts, raising the drain to a potential to no more than 5.0 volts, coupling the source region to ground potential, coupling the first well region of second conductivity type to ground potential, and placing the second well region at a potential below ground potential.

Abstract: A method of erasing electrically a programmable memory cell which cell includes a transistor formed in a region of semiconductor material. The transistor has a source region, a drain region, a floating gate, and a control gate. The method includes lowering the control gate to a potential no more negative than 6.5 volts, disconnecting the source and drain regions from any potential source, and placing the region of semiconductor material at a potential no more positive than 8.0 volts.

Abstract: A semiconductor structure for a flash memory has memory cells which are formed in a first conductivity type well, which in turn is formed within an opposite conductivity type well. The opposite conductivity type well is formed in the substrate. Additional regions within each of the first and opposite conductivity type wells are used to provide electrical connections to the corresponding well. This structure is particularly advantageous because it provides the ability to operate the flash memory with considerably lower operating potentials than prior art flash memories.

Abstract: An erase method provides for self-converging erase on a flash memory cell by rapidly switching a bias on a control gate while a lateral field is present in a channel region. Preferably, the lateral field is provided by differentially biasing the source and drain of the cell and the change in bias of the control gate is sufficiently fast to induce a transient response at the floating gate. The net transient vertical field formed across a tunneling oxide between the channel region and the floating gate causes moderate hot carrier injection between the channel region and the floating gate. This method is self-converging, since carrier injection to the floating gate will not happen unless a sufficient number of carriers are removed from the floating gate during the array step. Since the bulk of the self-converging effect occurs as the control gate voltage is transitioning and shortly thereafter, very little time is needed at the end of an erase pulse to effect this response.

Abstract: A Z-axis flywheel control of a computer input device, adapted to operate in a complex computer environment for handling computer file and application software selection and processing, includes a flywheel rotatably disposed inside the computer input device, a grating for detection the angular displacement of the flywheel representing the Z-axis movement and a position returning device for maintaining and returning the flywheel back to a default or home position.

Abstract: A process is described for fabricating an integrated circuit memory in a semiconductor substrate. In the substrate, a first well is formed by introduction of dopant opposite to conductivity of the substrate. Within the first well a second well is formed of conductivity type matching the substrate. The memory cells are fabricated in the second well and have source and drain regions opposite the conductivity type substrate. Each of the first and second wells also includes a region of corresponding conductivity type to enable separate electrical connections to be made to each of the wells.

Abstract: An erase method provides for self-converging erase on a flash memory cell by rapidly switching a bias on a control gate while a lateral field is present in a channel region. Preferably, the lateral field is provided by differentially biasing the source and drain of the cell and the change in bias of the control gate is sufficiently fast to induce a transient response at the floating gate. The net transient vertical field formed across a tunneling oxide between the channel region and the floating gate causes moderate hot carrier injection between the channel region and the floating gate. This method is self-converging, since carrier injection to the floating gate will not happen unless a sufficient number of carriers are removed from the floating gate during the array step. Since the bulk of the self-converging effect occurs as the control gate voltage is transitioning and shortly thereafter, very little time is needed at the end of an erase pulse to effect this response.

Abstract: The present method and apparatus provides a thin layer of oxynitride over a device including a patterned metal layer, application of a planarizing SOG layer over the thin oxynitride layer, removal of thin portions of the SOG layer by etching to expose portions of the thin oxynitride layer, and application of a thick oxynitride layer to form a strong bond with the thin oxynitride layer. A thin nitride layer, transparent to UV light, may then be applied to the resulting structure prior to application of plastic packaging material.

Abstract: Disclosed herein is a method of forming a silicon gate stack onto a silicon substrate for a silicon device. The method of forming the silicon gate stack comprises the steps of growing an oxide layer onto the silicon substrate, depositing a thin layer of silicon to form a thin layer of silicon over the oxide layer, depositing a thick layer of silicon over the thin layer of silicon, and introducing impurities into only the thick layer of silicon to form a silicon gate whereby the silicon gate includes the thin layer of silicon and the thick layer of silicon having the impurities. The impurities being introduced with a concentration, the impurities concentration and the thick layer thickness impeding an encroachment by the oxide layer into the silicon gate during application of a protective screen oxide layer around the silicon gate stack.

Abstract: Apparatus is provided to facilitate the process of bulk preprogramming each of the cells in a flash memory or a subblock of a flash memory. In the process, the source and drain of each cell to be preprogrammed is biased such that current need not be flowing between the source and drain through the cell's channel region for charge to be transferred between the cell's channel region and the cell's floating gate. In a specific embodiment, the sources and drains are left floating without any particular bias voltage and the control gates of the cells are set to between 9 and 12 volts above the substrate and held there for about 10 milliseconds (ms). In an alternate embodiment, the sources and drains of all of the cells to be preprogrammed are biased to the same potential, which is a negative voltage, ground, or a positive voltage.

Abstract: Disclosed herein is a method for forming an interconnect line having low conductor line capacitance between devices formed on an integrated circuit.

Abstract: After providing a patterned nitride layer over a patterned layer of oxide in turn disposed on a silicon substrate, a covering layer of oxide or polysilicon is deposited over the resulting structure to contact the substrate to hold the patterned nitride layer portions in position as field oxide is grown. In addition, field oxide growth rate slows at the edges of the nitride layer portions, allowing additional time for field oxide to flow as it is grown, relieving lifting force on the nitride layer portions, and providing an increase in silicon active area between field oxide regions.

Abstract: A method for reducing the steep step at the edge of a locally oxidized, field oxide boundary region as a result of using the local oxidation of silicon (LOCOS) method to isolate the active regions of a semiconductor wafer. The reduction is carried out by applying a planarizing layer to the field oxide layer and then etching back the planarizing layer and field oxide layer to a desired thickness.

Abstract: A silicon substrate has patterned thereon a pad oxide layer and a nitride layer. The exposed surface of the silicon substrate is cleaned of residual oxide, and a layer of oxidizable material such as polysilicon is deposit over the resulting structure. The polysilicon layer is anisotropically etched to form spacers on the side of the nitride layer portions, which are also in contact with the silicon substrate, the etching continuing into the silicon substrate. Field oxidation is then undertaken, with the polysilicon spacers being oxidized, as is a portion of the silicon substrate, the spacers causing initial oxidation during field oxide growth to be removed from the sides of the nitride layer portions, so that encroachment of the oxide under the nitride layer portions is avoided.

Abstract: A method for programming multiple values in an individual flash memory cell is disclosed. An individual flash cell is programmed by holding the bit line, corresponding to the particular memory cell to a value, V.sub.d, while the voltage on the control gate, V.sub.g, of the memory cell is varied. By varying the voltage on the control gate, multiple values are stored in the memory cell. The resulting values are self-convergent, therefore, verify circuitry becomes unnecessary.