摘要:
A series select transistor and a source select transistor are connected in series at the end of a NAND string of floating gate data storage transistors. The floating gates, the series select gate, and the source select gate are all preferably formed of polysilicon. The same tunnel oxide layer is used as gate oxide for the series select transistor and source select transistor as well as for the floating gate data storage transistors. Two layers of polysilicon in the series select gate and the source select gates are tied together. The series select transistor is tied to the last transistor in the NAND string. The source select transistor is tied to the array Vss supply. In order to program inhibit a specific NAND cell during the programming of another NAND cell, the gate of the series select transistor is raised to Vcc, while the gate of the source select transistor is held to ground. The two transistors in series are able to withstand a much higher voltage at the end of the NAND string without causing gated-diode junction or oxide breakdown in either the series or the source select transistor.
摘要:
A series select transistor and a source select transistor are connected in series at the end of a NAND string of floating gate data storage transistors. The floating gates, the series select gate, and the source select gate are all preferably formed of polysilicon. The same tunnel oxide layer is used as gate oxide for the series select transistor and source select transistor as well as for the floating gate data storage transistors. Two layers of polysilicon in the series select gate and the source select gates are tied together. The series select transistor is tied to the last transistor in the NAND string. The source select transistor is tied to the array Vss supply. In order to program inhibit a specific NAND cell during the programming of another NAND cell, the gate of the series select transistor is raised to Vcc, while the gate of the source select transistor is held to ground. The two transistors in series are able to withstand a much higher voltage at the end of the NAND string without causing gated-diode junction or oxide breakdown in either the series or the source select transistor.
摘要:
A series select transistor and a source select transistor are connected in series at the end of a NAND string of floating gate data storage transistors. The floating gates, the series select gate, and the source select gate are all preferably formed of polysilicon. The same tunnel oxide layer is used as gate oxide for the series select transistor and source select transistor as well as for the floating gate data storage transistors. Two layers of polysilicon in the series select gate and the source select gates are tied together. The series select transistor is tied to the last transistor in the NAND string. The source select transistor is tied to the array Vss supply. In order to program inhibit a specific NAND cell during the programming of another NAND cell, the gate of the series select transistor is raised to Vcc, while the gate of the source select transistor is held to ground. The two transistors in series are able to withstand a much higher voltage at the end of the NAND string without causing gated-diode junction or oxide breakdown in either the series or the source select transistor.
摘要:
The present invention facilitates programming of selected floating gate devices while successfully inhibiting the programming of unselected devices, without the need for growing multiple thicknesses of oxides. The preferred embodiment of the present invention utilizes a multiple select gate device. In particular, the select gate device is preferably a dual floating gate device rather than the conventional transistor (or device functioning as a conventional transistor) used in the current Flash memory systems as a select gate device.
摘要:
Methods are provided for significantly reducing electron trapping in semiconductor devices having a floating gate and an overlying dielectric layer. The methods form a nitrogen-rich region within the floating gate near the interface to an overlying dielectric layer. The methods include selectively introducing nitrogen into the floating gate prior to forming the overlying dielectric layer. This forms an initial nitrogen concentration profile within the floating gate. An initial portion of the overlying dielectric layer is then formed of a high temperature oxide (HTO). The temperature within the floating gate is purposely raised to an adequately high temperature to cause the initial nitrogen concentration profile to change due to the migration of the majority of the nitrogen towards the interface with the overlying dielectric layer and an interface with an underlying layer. Consequently, the floating gate is left with a first nitrogen-rich region near the interface to the overlying dielectric layer and a second nitrogen-rich region near the interface to the underlying layer. The first nitrogen-rich region has been found to reduce electron trapping within the floating gate, which could lead to false programming of the floating gate. Unlike a conventional thermally grown oxide film, the high temperature oxide film within the interpoly dielectric layer advantageously prevents the surface of the floating gate from becoming too granular. As such, the resulting interpoly dielectric layer, which typically includes several films, can be formed more evenly.
摘要:
Methods and arrangements are provided for introducing nitrogen into a tunnel oxide layer within a stacked gate structure of a non-volatile memory cell. The nitrogen is advantageously introduced into only a select portion of the tunnel oxide, preferably nearer the source region of the memory cell. This prevents the unwanted or residual nitrogen from detrimentally affecting other devices within the semiconductor integrated circuit.
摘要:
Methods and arrangements are provided for introducing nitrogen into a tunnel oxide layer within a stacked gate structure of a non-volatile memory cell. The nitrogen is advantageously introduced into only a select portion of the tunnel oxide, preferably nearer the source region of the memory cell. This prevents the unwanted or residual nitrogen from detrimentally affecting other devices within the semiconductor integrated circuit.
摘要:
Methods and arrangements are provided for significantly reducing electron trapping in semiconductor devices having a polysilicon feature and an overlying dielectric layer. The methods and arrangements employ a nitrogen-rich region within the polysilicon feature near the interface to the overlying dielectric layer. The methods include selectively implanting nitrogen ions through at least a portion of the overlying dielectric layer and into the polysilicon feature to form an initial nitrogen concentration profile within the polysilicon feature. Next, the temperature within the polysilicon feature is raised to an adequately high temperature, for example using rapid thermal anneal (RTA) techniques, which cause the initial nitrogen concentration profile to change due to the migration of the majority of the nitrogen towards either the interface with the overlying dielectric layer or the interface with an underlying layer. Consequently, the polysilicon feature has a first nitrogen-rich region near the interface to the overlying dielectric layer and a second nitrogen-rich region near the interface to the underlying layer. The migration of nitrogen further forms a contiguous reduced-nitrogen region located between the first nitrogen-rich region and the second nitrogen-rich region. The contiguous reduced-nitrogen region has a lower concentration of nitrogen than does the first nitrogen-rich region and the second nitrogen-rich region. The first nitrogen-rich region has been found to reduce electron trapping within the polysilicon feature. Thus, for example, in a non-volatile memory device wherein the polysilicon feature is a floating gate, false programming of the memory device can be significantly avoided by reducing the number of trapped electrons in the floating gate.
摘要:
In a memory device, a substrate has a plurality of source/drain regions in the substrate. Between the source/drain regions are trenches filled with oxide. Individual bit lines in the form of conductive regions are provided in the substrate, each bit line being under and running along the oxide in a trench. Each bit line connects to source/drain regions by means of connecting conductive regions extending from that bit line to source/drain regions.
摘要:
The present invention relates to a method of forming a stacked gate flash memory cell and comprises forming a tunnel oxide layer, a first conductive layer, an interpoly dielectric layer, and a second conductive layer in succession over a semiconductor substrate. The method further comprises forming a sacrificial layer over the second conductive layer, and patterning the sacrificial layer to form a sacrificial layer feature having at least one lateral sidewall edge associated therewith. A sidewall spacer is then formed against the lateral sidewall edge of the sacrificial layer, wherein the spacer has a width associated therewith, and the patterned sacrificial layer feature is removed. Finally, the second conductive layer, the interpoly dielectric and the first conductive layer are patterned using the spacer as a hard mask, and defining the stacked gate, wherein a width of the stacked gate is a function of the spacer width.