Abstract:
A method for forming a cell passes transistor in DRAM process disclosed. In one embodiment, the present invention provides a MOS structure, which can reduce junction leakage for P/N junction and increase the refreshes time capability. A method for DRAM fabrication comprises providing a semiconductor substrate having at least an isolation device therein. The isolation device defines an active area adjacent thereto on the semiconductor substrate. A first photoresist layer is formed on the semiconductor substrate, which exposes the active area in a first direction. The first conductive ions are implanted to form a well region in the semiconductor substrate, and the second conductive ions are implanted to form a field implant region in the semiconductor substrate. The third conductive ions are implanted to form a punchthrough implant region in the semiconductor substrate. Then the first photoresist layer is removed, and a second photoresist layer is formed on the semiconductor substrate. The second photoresist layer exposes the active area in a second direction different from the first direction. The fourth conductive ions are implanted to form a threshold implant region, and then the second photoresist layer is removed.
Abstract:
A process of fabricating a bottom electrode for the storage capacitors of DRAM is disclosed. The process includes first forming an insulation layer on the surface of the device substrate, with the insulation layer patterned to form a contact opening that exposes a source/drain region of the memory cell transistor. A first conductive layer then covers the insulation layer and fills into the contact opening, with the first conductive layer contacting the exposed source/drain region. A native oxide layer is then formed on the surface of the first conductive layer. A second electrically conductive layer is then formed and patterned to form a recess substantially above the location of the contact opening in the insulation layer. A layer of HSG—Si then covers the surface of the second conductive layer and the surface of the recess, and the HSG—Si layer and the second conductive layer are patterned to form the bottom electrode of the capacitor. The recess and its covering HSG—Si layer increase the effective surface area of the bottom electrode of the capacitor.
Abstract:
The present invention relates to a method of forming a contact hole of a DRAM on the semiconductor wafer. The semiconductor wafer comprises a substrate, a first dielectric layer, two bit lines on the first dielectric layer, a second dielectric layer, and a photo-resist layer comprising an opening to define the pattern of the contact hole. The method comprises performing a first anisotropic etching process to vertically remove a portion of the two dielectric layers and two bit lines to grossly form the contact hole, removing the photo-resist layer in its entirety, performing a thermal oxidation to form a silicon oxide layer on the side walls of the two bit lines, then forming a silicon nitride layer on the surface of the contact hole, and performing a dry etching to remove the silicon nitride layer. There is a silicon oxide layer and a silicon nitride layer between the bit line and the contact hole, and the contact area of the contact hole will not be reduced.
Abstract:
An improved method of fabricating a node capacitor for a dynamic random access memory (DRAM) process is disclosed. The process includes depositing a first interpoly dielectric (IPD1) layer over a substrate, patterning a first photoresist layer on the first interpoly dielectric layer, thereby defining a trench. A trench is etched in the first interpoly dielectric layer using the first photoresist layer as a mask. A first polysilicon layer is deposited on the first interpoly dielectric layer. The first polysilicon layer is etched to expose the first interpoly dielectric layer, then forming a landing pad over the substrate. In order to a polycide layer and a second interpoly dielectric (IPD2) layer are deposited, patterning a second photoresist layer, thereby defining a bit line structure. A bit line structure is formed, then depositing a spacer on the bit line structure. A second polysilicon layer is deposited, patterning a third photoresist layer, thereby defining a bottom electrode. A bottom electrode is formed, then depositing a thin NO (silicon nitride-silicon oxide) dielectric layer on the bottom electrode. An addition step is performed before forming the thin NO dielectric layer on the bottom electrode. In this additional step, a hemispherical grain (HSG) polysilicon layer is formed on the second polysilicon layer. This advantage is used to the hemispherical grain polysilicon layer increasing the area of a node capacitor. A third polysilicon layer is deposited completely covering the thin NO dielectric layer to form a top electrode.
Abstract:
A method of fabricating a dynamic random access memory includes forming a dummy layer over the isolation layer, in which the dummy layer has a higher etching selectivity than oxide. A dielectric layer is applied to isolate the bit lines. Then, a passivation layer is formed over the entire structure and a node contact opening is formed thereon. A liner oxide layer is then formed in the node contact opening to isolate the bit lines and the electrode of the capacitor. The node contact opening has a larger misalignment tolerance.
Abstract:
The present invention provides a fabricating method and structure of a dynamic random access memory. In this method, a substrate having a transistor thereon is provided. A bit line is formed on the substrate. The bit line is electrically coupled with the transistor through a contact hole. A second dielectric layer having a node contact opening is formed on the bit line. An etching step is performed to etch the bit line. A concave surface is formed on the sidewall of the bit line. Spacer layers are formed on the sidewalls of the node contact opening. Each spacer layer is used to insulate the concave surface. Thus, from the top-view layout, a portion of the node contact opening can overlap with the bit line. Thus, the size of DRAM is effectively reduced.
Abstract:
A method of fabricating a node contact window. A substrate having devices and a first dielectric layer is provided. Bit lines having spacer are formed on the first dielectric layer and a second is formed on the first dielectric layer. A hard material layer is then formed on the second dielectric layer. An opening is formed within the second dielectric layer to expose the spacer and the first dielectric layer. A polysilicon spacer is then formed on the sidewalls of the opening. A node contact window is formed by etching through the first dielectric layer to expose the substrate.
Abstract:
The present invention includes forming a first field oxide region (FOX) on a substrate. Buried N.sup.+ regions are then formed. Subsequently, a plurality of second FOX regions are formed. A tunneling window region between the second FOX regions is narrowed by the formation of the second FOX regions. Then a tunnel oxide is formed on the substrate. A first polysilicon layer is deposited on the first FOX, the second FOXs, the gate oxide, the tunnel oxide and the substrate. An etching step is used to define the floating gate. A dielectric layer is formed on the floating gate. A second polysilicon layer is then formed on the dielectric layer. The second polysilicon layer and the dielectric layer are etched. An ion implantation step is used to form source and drain of the gate.
Abstract:
A power supply device and an operating method thereof are provided. The power supply device includes a main converter and an auxiliary converter. The main converter includes a power factor corrector (PFC), a first capacitor that connects in parallel with the PFC and a DC/DC converter that connects in parallel with the first capacitor. The auxiliary converter is connected in parallel to the main converter. When the power supply device operates in a normal mode, the main converter and the auxiliary converter together provide a first output to an output load. When the power supply device is in a standby mode, the DC/DC converter is turned off so that only the auxiliary converter provides a second output to the output load. Meanwhile, the PFC is in operation to maintain the voltage of the first capacitor in order to meet the demand of the output dynamic response of the main converter.
Abstract:
An isolation layer is formed on a substrate of a semiconductor wafer. At least one recess is formed in the isolation layer by way of a photo-etching-process. A two stage in-situ doped deposition process is then performed to form a first doped amorphous silicon (&agr;-Si) layer and a second doped amorphous silicon (&agr;-Si) layer doping concentration of the second doped amorphous silicon (&agr;-Si) layer being less than that of the first doped amorphous silicon layer. A dielectric layer is formed to fill the recess, and a planarization process removes portions of the second doped amorphous silicon layer, the first doped amorphous silicon layer and the dielectric layer on the surface of the isolation layer. Finally, the dielectric layer and the isolation layer are removed, and a hemi-spherical grain (HSG) process is performed to form a rough surface with a plurality of hemi-spherical grains on the surface of the second doped amorphous silicon layer.