Abstract: A method for forming isolation structures in an integrated circuit, and the structures so formed, are disclosed. After definition of active regions of the surface is accomplished by provision of masking layers, recesses are etched into the exposed locations, to a depth on the order of the final thickness of the insulating isolation structure. Sidewall spacers of silicon dioxide, or another insulating amorphous material, are disposed along the sidewalls of the recesses, with silicon at the bottom of the recesses exposed. Selective epitaxial growth of silicon then forms a layer of silicon within the recesses, preferably to a thickness on the order of half of the depth of the recess. The epitaxial silicon is thermally oxidized, filling the recesses with thermal silicon dioxide, having a top surface which is substantially coplanar with the active regions of the surface.

Abstract: Local interconnect is defined in a polycrystalline silicon layer. Openings to underlying conducting regions are made through an insulating layer after the local interconnect conductor definition. A thin extra polycrystalline silicon layer is then deposited over the device and etched back to form polycrystalline silicon sidewall elements. These sidewalls connect the polycrystalline silicon local interconnect conductors to the underlying conductive regions. Standard silicidation techniques are then used to form a refractory metal silicide on the exposed underlying conductive regions, the polycrystalline silicon sidewall elements, and the polycrystalline silicon local interconnect conductors. This results in a complete silicided connection between features connected by the local interconnect conductors.

Abstract: A method is provided for depositing aluminum thin film layers to form improved quality contacts in a semiconductor integrated circuit device. All or some of the deposition process occurs at relatively low deposition rates at a temperature which allows improved surface migration of the deposited aluminum atoms. Aluminum deposited under these conditions tends to fill contact vias without the formation of voids. The low temperature deposition step can be initiated by depositing aluminum while a wafer containing the integrated circuit device is being heated from cooler temperatures within the deposition chamber.

Abstract: A silicide layer, to improve conductivity, is formed over a first layer of polycrystalline silicon, followed by a second layer of polycrystalline silicon. This structure is then patterned to form gate regions over active areas. A layer of metal silicide is formed over the entire surface of the chip, and patterned to form local interconnect. Etching of the second metal silicide layer is stopped by the second polycrystalline silicon layer, thereby protecting the first metal silicide layer from damage.

Abstract: A contact opening through an insulating layer is filled with metal and etched back to form a metal plug within the opening. A metal interconnect line can then be formed over the contact, and makes electrical contact with the metal plug. Since the contact opening is filled by the metal plug, it is not necessary for the metal signal line to have a widened portion in order to ensure enclosure.

Abstract: A method for forming integrated circuit structures includes the formation of high-value resistive elements and low resistance interconnect in a single polycrystalline layer. In one embodiment, interconnect regions of the polycrystalline silicon layer are masked, and resistive element regions are partially oxidized to reduce the thickness of the polycrystalline layer in such regions. Resistivity of the interconnect regions may then be reduced by implanting a high level of impurities in them, or by forming a refractory metal silicide layer over the interconnect regions. The oxide formed over the resistive elements during the oxidation thereof protects them from either of the following process steps, so that no masking is required. In an alternative embodiment, silicidation of the interconnect regions of the polycrystalline silicon layer may be performed without the prior local oxidations of the resistive element regions.

Abstract: A method for fabricating integrated circuits is used to improve contacts between polycrystalline interconnect and underlying polycrystalline or monocrystalline silicon regions. After contact openings are formed, a layer of titanium is deposited over the integrated circuit. The titanium is reacted in nitrogen to form a silicide layer only in the openings. Titanium nitride and unreacted titanium are then removed, and a layer of polycrystalline silicon deposited and patterned. The silicide layer between the polycrystalline interconnect and the underlying silicon ensures that a high quality contact is formed.

Abstract: A method for forming a thin oxide layer structure includes the step of first growing a dry oxide layer. A layer grown in steam and chlorine is formed next, followed by a final dry oxide layer. An anneal step in an inert gas further improves the quality of the oxide layer. The structure formed by such a process provides a layer of steam grown oxide sandwiched between two layers of oxide grown in a dry atmosphere.

Abstract: Field oxide regions are formed between active regions of a silicon substrate by forming over the substrate a sandwich of silicon dioxide, silicon nitride and silicon dioxide layers, opening the layers to expose a portion of the silicon substrate, removing a layer of the exposed substrate, forming side wall spacers on the edges of the opening, removing a layer of the silicon substrate exposed between the side wall spacers, and then reaching the exposed substrate for the thermal oxidation of the exposed substrate for forming the field oxide region. In those structures in which the field oxide is buried in the substrate as shown in FIG. 12, it may be feasible to use thicker field oxide regions and thereby to reduce the need for the heavily doped surface layer under the field oxide.

Abstract: A silicide layer, to improve conductivity, is formed over a first layer of polycrystalline silicon, followed by a second layer of polycrystalline silicon. This structure is then patterned to form gate regions over active areas. A layer of metal silicide is formed over the entire surface of the chip, and patterned to form local interconnect. Etching of the second metal silicide layer is stopped by the second polycrystalline silicon layer, thereby protecting the first metal silicide layer from damage.

Abstract: A method for forming a connection between two levels in a semiconductor structure includes first forming a VIA (14) through an insulating layer (12) to an underlying structure (10). Sidewall spacers (22) and (24) are formed on the vertical walls of the VIA (14). The spacers (22) and (24) have tapered surfaces. A barrier layer (30) is then formed over the bottom surface of the VIA followed by CVD deposition of a conductive layer (32) of WSi.sub.2 to provide a conformal conductive layer. An aluminum layer (38) is then deposited by physical vapor deposition techniques with the descending portions of layer (32) providing a conductive connection between the aluminum layer (38) and the lower structure (10) in the VIA (14).

Abstract: The method for producing the surface reflectance of the metal layer during semiconductor processing includes the step of roughening the surface of a metal layer prior to forming the photoresist thereon. The roughened surface reduces reflections that can cause metal notching effects. The step of roughening the surface includes depositing a layer (34) of aluminum which is substantially thinner than the thickness of the primary metal layer by a sputtering process.

Abstract: A process for forming a capping layer over a titanium silicide layer includes forming a layer of polysilicon (16) over a gate-oxide layer (14). A layer of titanium (18) is then formed over the poly layer (16) followed by deposition of a composite layer of tantalum silicide (20). The structure is then patterned and subjected to an annealing process to form a titanium silicide layer (22) covered by the capping layer (20) of tantalum silicide. The tantalum silicide provides a much higher oxidation resistant layer with the underlying titanium silicide providing the desirable conductive properties needed for long runs of interconnects on a semiconductor structure.

Abstract: A method for increasing the width of a transistor includes first forming a nitride cap (14) over the substrate (10) and then forming trenches (24) and (26) on either side of the cap (14) and having tapered sidewalls (28) and (30). A conformal layer of nitride (32) is formed over the substrate and then anisotropically etched to form sidewall layers (34) and (36). Field oxide is grown in the trenches with birds beaks (42) and (44) extending upward under the sidewall layers (34) and (36). A portion of the sidewalls (28) and (30) of the trenches remain such that the overall surface area between the edges of the birds beaks (42) and (44) is increased. A layer of strip oxide is then grown on the substrate to provide rounded edges (47) and (49). The strip oxide is then removed by a fifty percent over etch to cause the birds beaks (42) and (44) to recede, thus further increasing the surface area.

Abstract: A method for making a CMOS integrated circuit device saves on masking steps by using unmasked blanket implantations at various steps of the process, such as setting the threshold voltages of the transistors, forming a lightly doped drain for the N-channel transistor, and for forming the source/drain regions of the N-type transistor.