Abstract:
A gate structure for an ONO flash memory device includes a first layer of silicon oxide on top of a semiconductor substrate, a second layer of silicon oxide, a layer of silicon nitride sandwiched between the two silicon oxide layers, and a control gate on top of the second layer of silicon oxide. Nitrogen is implanted into the first layer of silicon oxide at less than normal energy levels to reduce the amount of damage to the underlying semiconductor substrate. After low energy nitrogen implantation, the semiconductor structure is heated to anneal out the implant damage and to diffuse the implanted nitrogen to the substrate and silicon oxide interface to cause SiN bonds to be formed at that interface. The SiN bonds is desirable because they improve the bonding strength at the interface and the nitrogen remaining in the silicon oxide layer increases the oxide bulk reliability.
Abstract:
A predetermined species such as nitrogen is placed at an interface between a bit line junction and a dielectric layer of a control dielectric structure of a flash memory device to minimize degradation of such an interface by minimizing formation of interface defects during program or erase operations of the flash memory device. The predetermined species such as nitrogen is implanted into a bit line junction of the flash memory device. A thermal process is performed that heats up the semiconductor wafer such that the predetermined species such as nitrogen implanted within the semiconductor wafer thermally drifts to the interface between the bit line junction and the control dielectric structure during the thermal process. The predetermined species such as nitrogen at the interface minimizes formation of interface defects and thus degradation of the interface with time during the program or erase operations of the flash memory device.
Abstract:
In a method of manufacturing a NOR flash memory, when the memory device dimensions are further reduced, the forming of spacers at two lateral sides of the gate structures is omitted, and a space between two gate structures can be directly filled up with a dielectric spacer or a shallow trench isolation (STI) layer. Therefore, it is possible to avoid the problem of increased difficulty in manufacturing memory device caused by forming spacers in an extremely small space between the gate structures. The method also enables omission of the self-alignment step needed to form the salicide layer. Therefore, the difficulty in self-alignment due to the extremely small space between the gate structures can also be avoided.
Abstract:
In a method of manufacturing a non-volatile memory cell, a self-aligned metal silicide is used in place of a conventional tungsten metal layer to form a polysilicon gate, and the self-aligned metal silicide is used as a connection layer on the polysilicon gate. By using the self-aligned metal silicide to form the polysilicon gate, the use of masks in the etching process may be saved to thereby enable simplified manufacturing process and accordingly, reduced manufacturing cost. Meanwhile, the problem of resistance shift caused by an oxidized tungsten metal layer can be avoided.
Abstract:
A single-poly non-volatile memory includes a storing node, a control node and a floating gate. While a programming operation is executed, a bit line is provided with a low voltage and a control line is provided with a high voltage so that a coupling voltage occurs in the floating gate. The voltage difference between the floating gate and the storing node is able to send electrons into the floating gate, but the voltage difference between the floating gate and the control node is not enough to expel electrons from the floating gate. While an erasing operation is executed, a bit line is provided with a high voltage and a control line is provided with a low voltage so that a coupling voltage occurs on the floating gate. The voltage difference between the floating gate and the storing node is able to expel electrons from the floating gate, but the voltage difference between the floating gate and the control node is not enough to send electrons into the floating gate.
Abstract:
A flash memory applied in NAND and/or NOR flash memory has a silicon-oxide-nitride-oxide-silicon cell structure, uses channel-hot-electron injection as a write mechanism thereof to have a localized trapping characteristic, and uses hot-hole injection as an erase mechanism thereof. The flash memory uses an oxide-nitride-oxide structure to replace a floating gate, and thereby solves the problem of an entire leakage caused by a local leakage of the floating gate. The flash memory may be miniaturized without the problem of data mutual interference, and may be easily integrated into the CMOS process to largely reduce the manufacturing cost thereof. Meanwhile, the flash memory also enables faster program time and erase time.
Abstract:
A non-volatile semiconductor memory device, which is intended to prevent data destruction by movements of electric charges between floating gates and thereby improve the reliability, includes element isolation/insulation films buried into a silicon substrate to isolate stripe-shaped element-forming regions. Formed on the substrate area floating gate via a first gate insulating film and further a control gate via a second gate insulating film. Source and drain diffusion layers are formed in self-alignment with control gates. The second gate insulating film on the floating gate is divided and separated together with the floating gate by slits above the element isolation/insulation films into discrete portions of individual memory cells. The select gate is formed with a STI recess process in advance locally in the select area.
Abstract:
A method of fabricating a memory device is described. During the process of forming the memory cell area and the periphery area of a semiconductor device a photoresist layer is formed on the memory cell area before the spacers are formed on the sidewalls of the gates. Therefore, the memory cell area is prevented from being damaged to mitigate the leakage current problem during the process of forming spacers in the periphery circuit area.
Abstract:
A memory device includes a conductive structure, a number of dielectric layers and a control gate. The dielectric layers are formed around the conductive structure and the control gate is formed over the dielectric layers. A portion of the conductive structure functions as a drain region for the memory device and at least one of the dielectric layers functions as a charge storage structure for the memory device. The dielectric layers may include oxide-nitride-oxide layers.
Abstract:
According to one exemplary embodiment, a structure comprises a first bit line and a second bit line. The structure further comprises a first memory cell situated over the first bit line, where the first memory cell comprises a first ONO stack segment, and where the first ONO stack segment is situated between the first bit line and a word line. The structure further comprises a second memory cell situated over the second bit line, where the second memory cell comprises a second ONO stack segment, where the second ONO stack segment is situated between the second bit line and the word line, and where the first ONO stack segment is separated from the second ONO stack segment by a gap. The first memory cell and the second memory cell may each be capable, for example, of storing two independent data bits.