Abstract: A method of fabricating an oxide-nitride-oxide (ONO) layer in a memory cell to retain charge well in the nitride layer includes the steps of forming a bottom oxide layer on a substrate, depositing a nitride layer and oxidizing a top oxide layer thereby causing oxygen to be introduced into the nitride layer. Another method includes the steps of forming a bottom oxide layer on a substrate, depositing a nitride layer and oxidizing a portion of a top oxide layer, thereby causing oxygen to be introduced into the nitride layer and depositing a remaining portion of the top oxide layer, thereby assisting in controlling the amount of oxygen introduced into the nitride layer. A further method includes the steps of forming a bottom oxide layer on a substrate, depositing a nitride layer, depositing a portion of a top oxide layer and oxidizing a remaining portion of the top oxide layer, thereby causing oxygen to be introduced into the nitride layer.

Abstract: A method for programming an array having a multiplicity of memory cells. The method includes, per cell to be programmed, verifying a programmed or non-programmed state of the cell and flagging those of the cells that verify as non-programmed during one of the verify steps after having previously verified as programmed. A programming pulse having a programming level is applied to the non-programmed cells which are not flagged cells. The steps of verifying, flagging and applying are then repeated until all of the cells verify as programmed at least once. Subsequently, a boost pulse having a boost programming level lower than the programming level is applied to the flagged cells.

Abstract: A symmetric memory array includes a multiplicity of repeating segments formed into rows and columns. Each segment includes a cell area formed of four segmented cell bit lines an even select area and an odd select area. The even select area is located at one end of the cell area and includes a segmented even contact bit line and two select transistors connecting the even contact bit line with the even cell bit lines of the segment. The odd select area is located at the opposite end of the cell area and includes a segmented odd contact bit line and two select transistors connecting the odd contact bit line with the odd cell bit lines of the segment. The array additionally includes one even contact connected to the even contact bit lines of two neighboring even select areas, one odd contact connected to the odd contact bit lines of two neighboring odd select areas and alternating even and odd metal lines connecting to the even and odd contacts, respectively.

Abstract: A nitride programmable read only memory (NROM) cell with a pocket implant self-aligned to at least one bit line junction. Alternatively, the bit line junction(s) can have a thin area of effective programming and erasing located nearby. Further alternatively, the channel can have a threshold voltage level implant which has a low voltage level in a central area of the channel and which has a peak of high voltage level near at least one of the bit line junctions. With one pocket implant, the NROM cell stores one bit. With two pocket implants, the NROM cell stores two bits.

Abstract: A delay device for delaying the activation of a sensing indication signal includes a reference word-line, a reference word-line driver, and a comparator. The reference word-line driver is controlled by a strobe signal, and is connected to the reference word-line and a reference word-line voltage. Additionally, when so indicated by the strobe signal, the reference word-line driver provides the reference word-line voltage to the reference word-line. The comparator is connected to the reference word-line and to the reference word-line voltage and activates the sensing indication signal when the voltage on the reference word-line is at least equal to a predetermined function of the reference word-line voltage.

Abstract: A nitride programmable read only memory (NROM) cell with a pocket implant self-aligned to at least one bit line junction. Alternatively, the bit line junction(s) can have a thin area of effective programming and erasing located nearby. Further alternatively, the channel can have a threshold voltage level implant which has a low voltage level in a central area of the channel and which has a peak of high voltage level near at least one of the bit line junctions. With one pocket implant, the NROM cell stores one bit. With two pocket implants, the NROM cell stores two bits.

Abstract: A dual bit read only memory cell has two bits separately stored in two different areas of the channel, such as the left and right bit line junctions of the channel. A programmed bit has a threshold pocket implant self-aligned to its bit line junction and an unprogrammed bit has no such implant. An array of such cells is manufactured by laying down a bit line mask and separately programming the two bit line junctions. For each bit line junction, the bit line junctions which are to remain unprogrammed are first covered, with a junction mask, after which the array is exposed to a threshold pocket implant at a 15-45° angle, to the right or to the left. The junction mask is removed and the process repeated for the other bit line junction. Finally, the bit line mask is removed. In an alternative embodiment, the threshold pocket implant is two implants, of two different materials.

Abstract: A method for detecting the content of a selected memory cell in a memory cell array includes the steps of charging a drain of the selected memory cell to a ground potential, charging a source of the selected memory cell to a predetermined voltage potential, detecting the voltage level on the drain and comparing the detected voltage level with a reference voltage level, thereby producing a comparison result.

Abstract: A method for manufacturing a memory array having a plurality of memory cells thereon and diffusion areas therebetween includes the steps of laying down a layer of silicon nitride, defining the diffusion areas and creating diffusion oxides over the diffusion areas. Both steps of laying down and defining occur without etching any part of the layer of silicon nitride. The step of creating diffusion oxides includes the steps of creating porous silicon nitride from portions of the silicon nitride layer wherever diffusion oxides are desired (typically by laying down photoresist in a desired pattern and bombarding the silicon nitride layer with ions) and oxidizing both the porous silicon nitride and the silicon substrate through the porous silicon nitride thereby to create silicon oxy-nitride and silicon dioxide, respectively. The present invention also includes a semiconductor chip having diffusion or bit line oxides formed of at least silicon oxy-nitride.

Abstract: A method for sensing a close to ground signal recieved from an array cell within a memory array includes the steps of providing a reference unit with a reference cell having a similar structure and a similar current path therethrough to that of the array cell, providing a timing unit with a timing cell having a similar structure and a similar current path therethrough to that of the array cell, discharging the array, the reference unit and the timing unit prior to charging them, generating a cell signal, a reference signal and a timing signal, respectively, upon charging, generating a read signal when the timing signal at least reaches a predefined voltage level and generating a sensing signal from the difference of the cell and reference signals once the read signal is generated. The reference unit has a reference capacitance which is a multiple of the expected capacitance of a bit line of the array and the timing unit has a predefined timing capacitance.

Abstract: A dual mode apparatus for alternately supplying a low power reference voltage and a high power reference voltage, both at the same voltage level. The apparatus includes a driver, an output buffer and a switch. The driver generates the low power reference voltage, which is directly supplied during a standby mode of a receiving unit. The output buffer receives the low power reference voltage during an active mode of the receiving unit, and generates the high power reference voltage therefrom. The switch is connected between an output of the driver and the output buffer, and provides the high power reference voltage during the active mode, and the low power reference voltage during the stand-by mode.

Abstract: The present invention is a device and method for a semiconductor array which attempts to ensure that, during power up, a reference cell becomes valid after one or more data cells. The array includes at least one data cell, at least one cell common line to which the data cell is connected, at least one reference cell, a reference common line to which the references cell is connected and a voltage differentiator. The voltage differentiator is connected to the cell and reference common lines and receives a powering-up power supply voltage from a power supply. The voltage differentiator provides a reference voltage to the reference common line and a cell voltage to the at least one cell common line, wherein the reference voltage is lower than the cell voltage by a predetermined voltage gap.

Abstract: A dual bit read only memory cell has two bits separately stored in two different areas of the channel, such as the left and right bit line junctions of the channel. A programmed bit has a threshold pocket implant self-aligned to its bit line junction and an unprogrammed bit has no such implant. An array of such cells is manufactured by laying down a bit line mask and separately programming the two bit line junctions. For each bit line junction, the bit line junctions which are to remain unprogrammed are first covered, with a junction mask, after which the array is exposed to a threshold pocket implant at a 15-45.degree. angle, to the right or to the left. The junction mask is removed and the process repeated for the other bit line junction. Finally, the bit line mask is removed. In an alternative embodiment, the threshold pocket implant is two implants, of two different materials.

Abstract: A non-volatile electrically erasable programmable read only memory (EEPROM) capable of storing two bit of information having a nonconducting charge trapping dielectric, such as silicon nitride, sandwiched between two silicon dioxide layers acting as electrical insulators is disclosed. The invention includes a method of programming, reading and erasing the two bit EEPROM device. The nonconducting dielectric layer functions as an electrical charge trapping medium. A conducting gate layer is placed over the upper silicon dioxide layer. A left and a right bit are stored in physically different areas of the charge trapping layer, near left and right regions of the memory cell, respectively.

Abstract: A method of fabricating a nitride read only memory (NROM) chip creates an oxide-nitride-oxide (ONO) layer on a substrate and etches the ONO layer within the memory portion of the chip into columns. Bit lines are implanted between columns after which bit line oxides are generated on top of the bit lines with the thickness of the bit line oxides being independent of the thickness of the bottom oxide. The thickness of a gate oxide layer in a periphery portion of the chip is also relatively independent of the thicknesses of the other oxides. Finally, rows of polysilicon or polysilicide are formed perpendicular to and on top of the bit line oxides and the ONO columns.

Abstract: A symmetric memory array includes a multiplicity of repeating segments formed into rows and columns. Each segment includes a cell area formed of four segmented cell bit lines an even select area and an odd select area. The even select area is located at one end of the cell area and includes a segmented even contact bit line and two select transistors connecting the even contact bit line with the even cell bit lines of the segment. The odd select area is located at the opposite end of the cell area and includes a segmented odd contact bit line and two select transistors connecting the odd contact bit line with the odd cell bit lines of the segment. The array additionally includes one even contact connected to the even contact bit lines of two neighboring even select areas, one odd contact connected to the odd contact bit lines of two neighboring odd select areas and alternating even and odd metal lines connecting to the even and odd contacts, respectively.

Abstract: A novel apparatus for and method of programming and reading a programmable read only memory (PRON) having a trapping dielectric sandwiched between two silicon dioxide layers is disclosed that greatly reduces the programming time of conventional PROM devices. Examples of the trapping dielectric are silicon oxide-silicon nitride-silicon oxide (ONO) and silicon dioxide with buried polysilicon islands. A nonconducting dielectric layer functions as an electrical charge trapping medium. This charge trapping layer is sandwiched between two layers of silicon dioxide acting as an electrical insulator. A conducting gate layer is placed over the upper silicon dioxide layer. The memory device is programmed in the conventional manner, using hot electron programming, by applying programming voltages to the gate and the drain while the source is grounded. Hot electrons are accelerated sufficiently to be injected into the region of the trapping dielectric layer near the drain.