Abstract: A nonvolatile semiconductor memory device according to the present invention has a control gate electrode which is formed on the upper stage of a stepped portion formed in the principal surface of a substrate with a first insulating film interposed therebetween and a floating gate electrode which is formed to cover up the stepped portion, capacitively coupled to the side surface of the control gate electrode closer to the stepped portion with a second insulating film interposed therebetween, and opposed to the lower stage of the stepped portion with a third insulating film serving as a tunnel film interposed therebetween.

Abstract: Presented in this invention is a fabricating method and its array organization for a high-density twin MONOS memory device integrating a twin MONOS memory cell array and CMOS logic device circuit. The invention consists of two fabrication methods, i) Simultaneous definition of memory gate and logic gate, thus improving the process integration scheme for easier and more reliable fabrication. ii) Bit line crosses word gate and control gate. The invention focuses on lowering parasitic sheet resistances to enable high speed while maintaining low manufacturing cost. The twin MONOS cell stores memory in two nitride memory cell elements underlying two shared control gates on both sidewalls of a select gate. The method is applicable to a device with a flat channel and/or a device having a step channel. Two embodiments of the present invention are disclosed.

Abstract: A semiconductor memory device includes a control gate electrode formed on a first main surface of a semiconductor substrate through a first insulating film, and a floating gate electrode covering a stepped region which connects the first main surface of the semiconductor substrate and a second main surface positioned at a lower level than the first main surface through a second insulating film and having a side surface capacitively coupled with one side surface of the control gate electrode through a third insulating film. The stepped region has a first stepped portion connected with the first main surface and a second stepped portion connecting the first stepped portion and the second main surface.

Abstract: A method for making a twin MONOS memory array is described where two nitride storage sites lay under the memory cell word gate. The fabrication techniques incorporate self alignment techniques to produce a small cell in which N+ diffusion the nitride storage sites are defined by sidewalls. The memory cell is used in an NAND array where the memory operations are controlled by voltages on the word lines and column selectors. Each storage site within the memory cell is separately programmed and read by application of voltages to the selected cell through the selected word line whereas the unselected word lines are used to pass drain and source voltages to the selected cell from upper and lower column voltages.

Abstract: In the present invention a twin MONOS metal bit line array is read and programmed using a three dimensional programming method with X, Y and Z dimensions. The word line address is the X address. The control gate line address is a function of the X and Z addresses, and the bit line address is a function of the Y and Z addresses. Because the bit lines and the control gate lines of the memory array are orthogonal a single cell can be erased with an adjacent memory, having the same selected bit and control gate lines, being inhibited from erase by application of the proper voltages to unselected word, control gate and bit lines.

Abstract: This invention provides a circuit and a method for providing an override voltage to control gates through boosting of a selected word line for TWIN metal oxide, nitride semiconductor MONOS memory. The boosted voltages are required to program, erase and read the 2-bit MONOS memory cell in this invention. This invention relates to providing a means of using capacitive coupling between selected word lines and neighboring control gates to boost the voltage for the program, erase and write modes of MONOS memory. Capacitive coupling to boost the voltage on the control gates adjacent to the selected word lines is used instead of generating the required boosted voltage through the control gate and bit line decoders and drivers. This voltage boosting method saves address decoder silicon area, decoder circuit complexity, reduces address decode set-up time, and eliminates the need for extra voltage supplies for address decoders.

Abstract: In this invention, by offering specific array-end structures and their fabrication method, the three resistive layers of diffusion bit line, control gate and word gate polysilicons, where control gate polysilicon can run on top of the diffusion bit line, are most effectively stitched with only three layers of metal lines keeping minimum metal pitches. The stitching method can also incorporate a bit diffusion select transistor and/or a control gate line select transistor. The purpose of the select transistors may be to reduce the overall capacitance of the bit line or control gate line, or to limit the disturb conditions that a grouped sub-array of cells may be subjected to during program and/or erase.

Abstract: In the prior arts a twin MONOS memory erase is achieved by applying a positive bias to the bit diffusion and a negative bias to the control gate. The other word gate and substrate terminals are grounded. But the voltage of word gate channel adjacent to the control gate can dramatically influence erase characteristics and speed, due to the short control gate channel length, which is a few times of the carrier escape length. A negative voltage application onto the word gate enhances erase speed, whereas a positive channel potential under the word gate reduces erase speed. By effective biasing of the memory array, word line or even single memory cell level erase is possible without area penalty, as compared to erase blocking by triple well or physical block separations of prior art. Near F-N channel erase without substrate bias application and program disturb protection by word line voltage are also included.

Abstract: A non-volatile semiconductor storage device includes a semiconductor substrate provided with a step portion in an upper portion thereof, and having a first region that is an upper level of the step portion and a second region that is a lower level thereof, a control gate electrode formed on the first region of the semiconductor substrate via a gate insulating film, and a floating gate electrode formed on the side face of the control gate electrode on the side of the step portion and on the step portion via an insulating film. The side face of the step portion forms an obtuse angle with respect to the upper surface of the second region, and the insulating film has a substantially uniform thickness on the step portion.

Abstract: An fast program, ultra-high density, dual-bit, multi-level flash memory process, which can be applied to a ballistic step split gate side wall transistor, or to a ballistic planar split gate side wall transistor, which enables program operation by low voltage requirement on the floating gate during program is described. Two side wall floating gates are paired with a single word line select gate, and word lines are arranged to be perpendicular both the bit lines and control gate lines. Two adjacent memory cells on the same word line do not require an isolation region. Also, the isolation region between adjacent memory cells sharing the same bitline is defined by the minimum lithography feature, utilizing a self align fill technique. Adjacent memory cells on the same word line share bitline diffusion as well as a third poly control gate. Control gates allow program and read access to the individual floating gate.

Abstract: An fast program, ultra-high density, dual-bit, multi-level flash memory process, which can be applied to a ballistic step split gate side wall transistor, or to a ballistic planar split gate side wall transistor, which enables program operation by low voltage requirement on the floating gate during program is described. Two side wall floating gates are paired with a single word line select gate, and word lines are arranged to be perpendicular both the bit lines and control gate lines. Two adjacent memory cells on the same word line do not require an isolation region. Also, the isolation region between adjacent memory cells sharing the same bitline is defined by the minimum lithography feature, utilizing a self align fill technique. Adjacent memory cells on the same word line share bitline diffusion as well as a third poly control gate. Control gates allow program and read access to the individual floating gate.

Abstract: The present invention provides a method of memory cell selection and operation to obtain wide program bandwidth and EEPROM erase capability. Two storage sites within a memory cell can be simultaneously selected during read, program and erase. By proper biasing, each of the sites can be independently read and programmed. Also, during program, the source of energy to produce the current flow can be dynamically obtained from the stored charge on the selected bit line. If the bit line capacitance is not adequate to provide a charge that is necessary, additional bit line capacitance is borrowed from unselected bit lines, or a source follower select transistor may be used.

Abstract: Presented in this invention is a fabricating method and its array organization for a high-density twin MONOS memory device integrating a twin MONOS memory cell array and CMOS logic device circuit.

Abstract: The present invention provides a method of memory cell selection and operation to obtain wide program bandwidth and EEPROM erase capability. Two storage sites within a memory cell can be simultaneously selected during read, program and erase. By proper biasing, each of the sites can be independently read and programmed. Also, during program, the source of energy to produce the current flow can be dynamically obtained from the stored charge on the selected bit line.

Abstract: A method of stably and uniformly erasing a non-volatile memory or memory array in a gate insulator in which carrier-trapping sites for carrier storage are furnished is described. A first method of the invention is the application of a discharge pulse(s) to a gate after erasure where the discharge pulse(s) discharges unstable holes injected into the gate insulator. A second method of the invention is injection of electrons into the trap sites of all the cells in a memory array to be erased before erasure. This makes Vth distribution across the memory array uniform after erasure. A third method of the invention is a reduced bias approach to erase stably the electrons stored in the trap sites. This includes not only literally “erase,” but also “annihilate or neutralize” trapped electron charge by hole charge.

Abstract: The nonvolatile semiconductor memory device has a floating gate electrode that is formed on the semiconductor region and stores carriers injected from the semiconductor region and a control gate electrode that controls the quantity of stored carriers by applying a predetermined voltage to the floating gate electrode. The source region is formed in the semiconductor region on one of side regions of the floating gate electrode and control gate electrode, while the drain region is formed on the other of the side regions thereof. The drain region creates an electric field from which the carriers injected into the floating gate electrode are subject to an external force having an element directed from the semiconductor region to the floating gate electrode.

Abstract: In the present invention a new method for program and program verify is described. The threshold voltage of the memory cell is shifted up and then measured with minimal charging and discharging of the bit lines and control gate lines. Bit line to control gate line capacitance is also used to reduce the number of voltage references needed. Program current is reduced by use of a load device coupled to the source diffusion. The result is increased program bandwidth with lower high voltage charge pump current consumption.

Abstract: A nonvolatile semiconductor memory device according to the present invention has a control gate electrode which is formed on the upper stage of a stepped portion formed in the principal surface of a substrate with a first insulating film interposed therebetween and a floating gate electrode which is formed to cover up the stepped portion, capacitively coupled to the side surface of the control gate electrode closer to the stepped portion with a second insulating film interposed therebetween, and opposed to the lower stage of the stepped portion with a third insulating film serving as a tunnel film interposed therebetween.

Abstract: In the prior arts a twin MONOS memory erase is achieved by applying a positive bias to the bit diffusion and a negative bias to the control gate. The other word gate and substrate terminals are grounded. But the voltage of word gate channel adjacent to the control gate can dramatically influence erase characteristics and speed, due to the short control gate channel length, which is a few times of the carrier escape length. A negative voltage application onto the word gate enhances erase speed, whereas a positive channel potential under the word gate reduces erase speed. By effective biasing of the memory array, word line or even single memory cell level erase is possible without area penalty, as compared to erase blocking by triple well or physical block separations of prior art. Near F-N channel erase without substrate bias application and program disturb protection by word line voltage are also included.

Abstract: Provided in the present invention are a high speed and low program voltage nonvolatile memory cell, a programming method for same and a nonvolatile memory array. A nonvolatile memory cell comprises a first gate insulator formed on a surface of a first channel forming semiconductor region adjacent to a source region; a second gate insulator formed on a surface of a second channel forming semiconductor region adjacent to a drain region; a first gate electrode formed on said first gate insulator; and a second gate electrode formed on said second gate insulator wherein the second gate insulator includes a first layer forming a potential barrier at the interface with the second channel forming region; a third layer forming a potential barrier at the interface with the second gate electrode and the second layer between the first and third layers forming a carrier trapping level.