Abstract: The preferred embodiments of the present invention overcome the limitations of the prior art by providing a method for forming the source/drain diffusions in a vertical transistor structure that results in improved channel length uniformity. In one embodiment, the present invention is used to form source/drain and bitline diffusion structures for use in pillar memory cells. Additionally, in another embodiment, the present invention is used to form source/drain and plate diffusion structures in pillar memory cells. Both preferred embodiments deposit conformal photoresist on a pillar structure and use an off-axis exposure process to recess a dopant source layer to the proper depth along the pillar. The recessed dopant source layer can then be used to form the source/drain/bitlines diffusions or source/drain/plate diffusions in the pillar memory device.

Abstract: High integrity shallow source/drain junctions are formed employing cobalt silicide contacts. Embodiments include depositing a layer of cobalt on a substrate above intended source/drain regions, depositing a cap layer of titanium or titanium nitride on the cobalt, depositing a doped film on the cap layer, and performing silicidation, as by rapid thermal annealing, to form a low-resistivity cobalt silicide and to diffuse impurities from the doped film through the cobalt silicide into the substrate to form a junction extending into the substrate a constant depth below the cobalt silicide interface. The formation of source/drain junctions self-aligned to the cobalt silicide/silicon interface prevents junction leakage while allowing the formation of cobalt silicide contacts at optimum thickness, thereby facilitating reliable device scaling.

Abstract: A self-aligned dielectric spacer is etched by providing capped gate structure along a second layer of dielectric material located above the gate cap material. Dopant material at an increased doping level is provided in the second layer of dielectric material where the self-aligned spacer is to be located. The second layer of dielectric material is then etched selective to the dopant to define the self-aligned dielectric spacer.

Abstract: A DRAM cell capacitor is described. Capacitor formation and cell insolation methods are integrated by using existing isolation trench sidewalls to form DRAM capacitors. A doped silicon substrate adjacent to the vertical sidewalls of the isolation trench provides one DRAM cell capacitor plate. The DRAM capacitor also contains a dielectric material that partially covers the interior vertical sidewalls of the isolation trench. A conductive layer covering the dielectric material on the vertical sidewalls of the isolation trench forms the second capacitor plate and completes the DRAM capacitor.

Abstract: A memory cell including a substrate, at least one deep trench capacitor in the substrate, at least one FET in the substrate disposed over at least a portion of the at least one deep trench capacitor, and at least one isolation region in the substrate surrounding the at least one FET and having a greater depth than the at least one FET. The at least one FET includes a gate disposed over at least a portion of the at least one deep trench capacitor and doped regions arranged on adjacent sides of the gate and separated from the gate by an insulating layer.

Abstract: Doped semiconductor with high dopant concentrations in small semiconductor regions without excess spreading of the doped region are formed by:(a) applying a dopant-containing oxide glass layer on the semiconductor surface,(b) capping the dopant-containing oxide glass layer with a conformal silicon oxide layer,(c) heating the substrate from step (b) in a non-oxidizing atmosphere whereby at least a portion of the dopant in the glass diffuses into the substrate at the semiconductor surface, and(d) heating the glass-coated substrate from step (c) in an oxidizing atmosphere whereby at least a portion of the dopant in the glass near the semiconductor surface is forced into the substrate at the semiconductor surface by diffusion of oxygen through the glass.The method is especially useful for making buried plates in semiconductor substrates which may be used in trench capacitor structures. The preferred semiconductor substrate material is monocrystalline silicon. The preferred dopant is arsenic.

Abstract: A memory cell is constructed with one electrode of the transfer device extending over a trench capacitor, saving about 6.5% of cell area. Selective polysilicon for a strap seeded from the trench is grown in the same step in which selective single crystal silicon seeded from the substrate is grown for the transfer device. At least a portion of the node diffusion is located in single crystal epitaxial silicon extending over the trench. The process eliminates the need for a separate strap masking step.

Abstract: A method for forming a capacitor in a semiconductor body is provided. The method includes the step of forming a trench in a portion of a surface of the semiconductor body. The trench having sidewalls and a bottom. A doped film is deposited over the surface of the semiconductor body. Portions of the doped film are deposited over the sidewalls and bottom of the trench. The semiconductor body is heated and the doped film to produce a liquid phase interface region therebetween while diffusing dopant in the doped film into a region of the semiconductor body. The interface region is cooled to return such interface region to a solid phase. The doped film and the interface region are removed from the semiconductor body while leaving the doped region in the semiconductor body. A dielectric film is deposited over the doped region of the semiconductor body.

Abstract: The method sequence results in a conductive connection between two zones of a first conductivity type. In particular, one of the zones is a source/drain zone of a transistor. Instead of the conventional additional nitride layer, the connection is produced by implanting directly into the third insulation layer, which is present anyway, and by utilizing the fact that the third insulation layer forms the lateral spacers on the gatestack disposed on the region of the second conductivity type.

Abstract: A dynamic random access memory (DRAM) cell is formed with a buried strap which is routed through an isolation trench. This structure frees space in the transfer gate such that the location of the buried strap is not a limiting factor for decreasing the size of DRAM cells.

Abstract: Method for forming three-dimensional device structures comprising a second device having sub-groundrule features formed over a first device is disclosed. A layer having a single crystalline top surface is formed above the first device to provide the base for forming the active area of the second device. the sub-groundrule feature is formed using mandrel and spacers.

Abstract: A method for forming a contact is disclosed. A buried impurity region of a second conductivity type is formed in a semiconductor substrate of a first conductivity type. First and second well regions of a first and second conductivity types, respectively, are also formed in the semiconductor substrate. The second well region overlaps the first well region and contacts and surrounds the buried impurity region. A surface impurity concentration of the first well region is greater than a surface impurity concentration of the second well region. A contact to the second well region is formed.

Abstract: To produce a silicon capacitor, hole apertures at whose surface a conductive zone (40) is formed by doping and whose surface is provided with a dielectric layer (6) and a conductive layer (7) are generated in an n-doped silicon substrate (1). To compensate for mechanical strains in the silicon substrate (1) brought about by the doping of the conductive zone (40), the conductive zone (40) is additionally doped with germanium which is outdiffused from a germanium-doped layer.

Abstract: In a method for making an electrical connection between a trench storage capacitor and an access transistor in a DRAM cell, the electrical connection is formed through the selectively controlled outdiffusion of either N-type or P-type dopants present in the trench through a single crystalline semiconducting material which is grown by epitaxy (epi) from the trench sidewall. This epitaxially grown single crystalline layer acts as a barrier to excessive dopant outdiffusion which can occur in the processing of conventional DRAMs.

Abstract: A method for making an electrical connection between a trench storage capacitor and an access transistor in a DRAM cell. The electrical connection is formed through the selectively controlled outdiffusion of either N-type or P-type dopants present in the trench through a single crystalline semiconducting material which is grown by epitaxy (epi) from the trench sidewall. This epitaxially grown single crystalline layer acts as a barrier to excessive dopant outdiffusion which can occur in the processing of conventional DRAMs.

Abstract: A method of forming a DRAM storage cell with a trench capacitor in an SOI substrate is taught. The method involves forming an field effect transistor (FET) consisting of a source, drain, channel regions in a device layer, a gate oxide layer on the surface of the device layer and a gate electrode over the channel region.

Abstract: A method is provided for forming planar, self-aligned spaced-apart wells without a high temperature oxidation step to form an ion barrier. The method comprises preparing a substrate with a silicon dioxide-polysilicon-silicon dioxide barrier layer that can be etched to expose different sublayers of the barrier at selected junctures in the production process. A single masking step defines the location of a first set of wells on the prepared substrate. The outer silicon dioxide layer is etched to expose the polysilicon layer at the selected locations, and the substrate is implanted to form the first set of wells. Following ion implantation, the substrate photo-resist is removed, and the substrate is exposed to a germanium-silicon mixture under conditions selected to preferentially deposit a germanium-silicon alloy barrier layer on the exposed polysilicon layer.

Abstract: A method is described for making an array of dynamic random access memory (DRAM) cells having a trench/stacked capacitor within each cell. The method involves forming trenches in the silicon substrate at the capacitor node contact areas of the DRAM cells, and using liquid phase deposition (LPD) of silicon oxide in the trenches to form oxide plugs that extend upward into the openings in the photoresist mask used to etch the trenches. After removing the photoresist, polysilicon sidewall spacers are formed on the LPD oxide plugs. The sidewall spacers become part of the stacked capacitor structures. Another patterned polysilicon layer is used to form the array of storage-node electrodes for the stacked capacitors, and also serve as the storage-node electrodes for the trench capacitors. Conventional methods are used to complete the array of trench/stacked capacitors by depositing an interelectrode dielectric layer and then forming the polysilicon top electrodes.