摘要:
The process comprises a sequence of steps initiated by forming a word line mask on the surface of a substrate of a first conductivity type. Ions are implanted to form word lines covered by a dielectric layer. A polysilicon layer doped with a given conductivity type on the dielectric layer is formed on a second dielectric layer on the polysilicon layer. Bit lines are formed with a different conductivity type in the polysilicon layer. Forming a code mask above the polysilicon layer with openings above predetermined regions, etched through the mask to remove predetermined regions in the first polysilicon layer, whereby the ROM is encoded. Preferably, a combined silicon dioxide and silicon nitride layer is formed above the polysilicon layer before forming the code mask. Preferably, the silicon dioxide is deposited first, patterned and used as a mask for forming dopant patterns in the polysilicon layer through openings therein. Preferably, a layer of silicon nitride is deposited upon the silicon dioxide to a greater thickness than the silicon dioxide and is then planarized. Preferably, the dielectric layer formed above the word lines comprises a gate oxide layer.
摘要:
Systems and methods for processing alert communications are provided herein. Some exemplary methods may include processing alert communications on a mobile client computing device, where the mobile client computing device having a mobile survey management application. The method may also include executing instructions stored in memory to: capture at least a portion of an electronic mail alert communication provided to the mobile client computing device, the electronic mail alert communication being provided to the mobile client computing device by a survey management application of an application server, to establish an active issue within the mobile survey management application, and provide notification to the survey management application that the active issue has been resolved.
摘要:
A flash memory structure comprises a first polysilicon layer above a semiconductor substrate; a thin dielectric layer above the first polysilicon layer; and a second polysilicon layer across and above the dielectric layer and the substrate, wherein the second polysilicon layer has a linear shape when viewed from the top. The memory structure further comprises a drain region in the semiconductor substrate on one side of the second polysilicon layer; a trench isolation structure for insulating from neighboring devices; a buried metallic layer located inside a portion of the trench isolation structure close to the upper surface of the substrate; and a common source region located on the other side of the first polysilicon layer just opposite the drain region such that the common source region at least includes a source region and a buried metallic layer alternately linked together.
摘要:
An improved method for fabricating a flash memory on a semiconductor substrate is provided. A patterned gate oxide layer and a patterned mask layer are formed on the substrate. Hard material spacers are formed on sidewalls of the gate oxide layer and the mask layer. A shallow trench isolation is formed in the substrate using the mask layer and the hard material spacers as masks. The hard material spacers and the mask layer are removed. A tunneling oxide layer is formed on a portion of the substrate beside the gate oxide layer. A floating gate is formed over the gate oxide layer and the tunneling oxide layer. A dielectric layer is formed over the floating gate. A control gate is formed over the dielectric layer.
摘要:
A method of forming data storage capacitors in DRAM cells, which data storage capacitors each have an increased surface area for the charge storage plates of the capacitors in order to increase the capacitance. The individual method allows ULSI (Ultra Large Scale Integration) DRAMs, although reduced in circuit element size, to be formed with data storage capacitors having a sufficiently large capacitance to reliably retain electric charges. In this method, a double-trench structure is formed in at least two overlaying conductive layers serving as a bottom plate of the data storage capacitor. A dielectric layer is then formed over the bottom plate, and subsequently, another conductive layer serving as a top plate of the data storage capacitor is formed over the dielectric layer. In this semiconductor structure, the double-trench structure in the data storage capacitor increases the surface area of the bottom plate, thus proportionally increasing the capacitance of the data storage capacitor.
摘要:
A flash memory cell. A heavily doped region with the opposite polarity of the drain region is formed between the channel region and the drain region. The heavily doped region is in a bar shape extending towards both the drain and the source regions along a side of the floating gate. Furthermore, the reading operation is performed in reverse by applying a zero voltage to the drain region, and a non-zero voltage to the source region.
摘要:
A method of fabricating a dynamic random access memory is disclosed, which mainly utilizing selective liquid-phase deposition process to form an insulation layer on the gate electrode structure.
摘要:
A method of manufacturing a flash memory structure that also includes the process of forming a shallow trench isolation structure. The method comprises the steps of providing a semiconductor substrate, and then forming a shallow trench isolation structure within the substrate. Thereafter, etching is carried out to form a shallow trench within a portion of the shallow trench isolation structure. The shallow trench is formed where a common source terminal is subsequently formed. Next, metallic material is deposited into the trench to form a buried metallic layer. Then, a stacked gate is formed above the semiconductor substrate. Finally, ions are implanted into the substrate on each side of the stacked gate using the stacked gate itself as a mask to form a source region and a drain region. The source region and the buried metallic layer are connected together to form a common source region. The process of forming the buried metallic layer in the substrate not only is compatible with the process of forming a shallow trench isolation structure, but the device so formed also takes up less chip area. Hence, a device array having a higher density can be produced.
摘要:
A method of forming a shallow trench isolation in a semiconductor substrate. A mask layer is formed to cover an active region of the substrate. A trench is formed within the exposed substrate. The trench is filled with an insulation layer. The dimension of the mask layer is shrunk. A thermal oxidation process is performed to form an oxide protrusion between the trench and the active region. The mask layer is removed.
摘要:
A mask ROM uses a bit line structure having a vertically graded dopant distribution or a distinct two level dopant distribution. A bit line might include a highly doped region buried deeply within the substrate that is connected to a comparatively lightly doped region formed above the more highly doped region. The vertical structure of the bit line allows the bit line to be less resistive than the simpler shallow bit line structure conventionally used. The vertical structure (i.e., the two level or graded structure) of the bit line allows the bit line to have a lower doping immediately adjacent the channel region, which reduces the likelihood of punchthrough. The deeper, highly doped portions of the bit line are narrow and laterally confined so that well defined antipunchthrough implantations can be formed which lie between but separated from the more highly doped portions of the bit lines. This aspect of the structure reduces the likelihood of punchthrough while limiting the extent of overlap between the buried bit lines and the antipunchthrough implantation.