Abstract: A method for processing a semiconductor memory device is disclosed, the memory device including an array area and a support area thereon. In an exemplary embodiment of the invention, the method includes removing, from the array area, an initial pad nitride material formed on the device. The initial pad nitride material in the support area, however, is still maintained. Active device areas are then formed within the array area, wherein the initial pad nitride maintained in the support area helps to protect the support area from wet etch processes implemented during the formation of active device areas within the array area.

Abstract: The vertical MOSFET structure used in forming dynamic random access memory comprises a gate stack structure comprising one or more silicon nitride spacers; a vertical gate polysilicon region disposed in an array trench, wherein the vertical gate polysilicon region comprises one or more silicon nitride spacers; a bitline diffusion region; a shallow trench isolation region bordering the array trench; and wherein the gate stack structure is disposed on the vertical gate polysilicon region such that the silicon nitride spacers of the gate stack structure and vertical gate polysilicon region form a borderless contact with both the bitline diffusion region and shallow trench isolation region. The vertical gate polysilicon is isolated from both the bitline diffusion and shallow trench isolation region by the nitride spacer, which provides reduced bitline capacitance and reduced incidence of bitline diffusion to vertical gate shorts.

Abstract: Processing of a DRAM device containing vertical MOSFET arrays proceeds through planarization of the array gate conductor (GC) polysilicon of the vertical MOSFET to the top surface of the top oxide. A thin polysilicon layer is deposited over the planarized surface and an active area (M) pad nitride and tetraethyl orthosilicate (TEOS) stack is deposited. The M mask is used to open the pad layer to the silicon surface, and shallow trench isolation (STI) etching is used to form isolation trenches. An AA oxidation is performed, the isolation trenches are filled with high density plasma (HDP) oxide and planarized to the top surface of the AA pad nitride. Following isolation trench (IT) planarization, the AA pad nitride is stripped, with the thin silicon layer serving as an etch stop protecting the underlying top oxide. The etch support (ES) nitride liner is deposited, and the ES mask is patterned to open the support areas. The ES nitride, thin polysilicon layer and top oxide are etched from the exposed areas.

Abstract: A method for processing a semiconductor memory device is disclosed, the memory device including an array area and a support area thereon. In an exemplary embodiment of the invention, the method includes removing, from the array area, an initial pad nitride material formed on the device. The initial pad nitride material in the support area, however, is still maintained. Active device areas are then formed within the array area, wherein the initial pad nitride maintained in the support area helps to protect the support area from wet etch processes implemented during the formation of active device areas within the array area.

Abstract: The vertical MOSFET structure used in forming dynamic random access memory comprises a gate stack structure comprising one or more silicon nitride spacers; a vertical gate polysilicon region disposed in an array trench, wherein the vertical gate polysilicon region comprises one or more silicon nitride spacers; a bitline diffusion region; a shallow trench isolation region bordering the array trench; and wherein the gate stack structure is disposed on the vertical gate polysilicon region such that the silicon nitride spacers of the gate stack structure and vertical gate polysilicon region form a borderless contact with both the bitline diffusion region and shallow trench isolation region. The vertical gate polysilicon is isolated from both the bitline diffusion and shallow trench isolation region by the nitride spacer, which provides reduced bitline capacitance and reduced incidence of bitline diffusion to vertical gate shorts.

Abstract: A structure and method which enables the deposit of a thin nitride liner just before Trench Top Oxide TTO (High Density Plasma) HDP deposition during the formation of a vertical MOSFET DRAM cell device. This liner is subsequently removed after TTO sidewall etch. One function of this liner is to protect the collar oxide from being etched during the TTO oxide sidewall etch and generally provides lateral etch protection which is not realized in the current processing scheme. The process sequence does not rely on previously deposited films for collar protection, and decouples TTO sidewall etch protection from previous processing steps to provide additional process flexibility, such as allowing a thinner strap Cut Mask nitride and greater nitride etching during node nitride removal and buried strap nitrided interface removal.

Abstract: A method for forming an oxide of substantially uniform thickness on at least two crystallographic planes of silicon, in accordance with the present invention, includes providing a substrate where silicon surfaces have at least two different crystallographic orientations of the silicon crystal. Atomic oxygen (O) is formed for oxidizing the surfaces. An oxide is formed on the surfaces by reacting the atomic oxygen with the surfaces to simultaneously form a substantially uniform thickness of the oxide on the surfaces.

Abstract: A method for forming isolation trenches for a semiconductor device forms, in a substrate, a plurality of trenches having different widths including widths above a threshold size and widths below a threshold size. The plurality of trenches have a same first depth. A masking layer is deposited in the plurality of trenches, the masking layer has a thickness sufficient to both line the trenches with the widths above the threshold size and completely fill the trenches with the widths below the threshold size. A portion of the substrate is exposed at a bottom of the trenches with the widths above the threshold size by etching the masking layer. The plurality of trenches is etched to extend the trenches with the widths above the threshold size to different depths.