Abstract: There is provided a semiconductor device comprising, for example, a MOS structure having a low electrical resistance in contacts and local interconnects, and a method for fabricating the device. When openings are formed in a dielectric region of a MOS structure, the thin metal silicide layer on top of a drain/source region is diminished due to the limited selectivity of the etch process and the need to over-etch to obtain appropriate electrical contacts. Consequently, the contact resistance is increased resulting in an increased contact resistance. Therefore, a bilayer metal is deposited on the metal silicide layer and the surface of the openings, wherein the metal layer that is in contact with the metal silicide layer is preferably the same metal as the metal of the metal silicide layer. In a subsequent annealing process, the metal of the bilayer partially converts into metal silicide, thereby increasing the initial metal silicide layer and concurrently reducing the contact resistance.

Abstract: A method is disclosed in which a low-resistance portion of the gate electrode of a transistor is formed independently of the formation of low-resistance portions in the drain and source regions. Accordingly, the device features a thick low-resistance portion in the gate electrode, for example, a thick gate silicide for supporting low gate delays by minimizing the gate resistance, and a thin low-resistance portion in the drain and source in order to meet the requirements for shallow junction integration. Moreover, a transistor is disclosed having a low-resistance gate electrode portion, the composition of which is different from the low-resistance portion of the drain and source.

Abstract: A method is described which can be used to form gate structures of very small dimensions in a semiconductor device. The method may be used to avoid employment of highly-sophisticated and cost-intensive DUV photolithography. In one illustrative embodiment, the method comprises forming a gate electrode layer, forming a first mask layer above the gate electrode layer, and forming a sidewall spacer adjacent the sidewalls of the first mask layer. Thereafter, the method comprises forming a second mask layer above a portion of the sidewall spacer and the first mask layer, removing portions of the sidewall spacer to define a hard mask comprised of a portion of the sidewall spacer, and patterning the gate electrode layer using the hard mask to define a gate electrode of the device.

Abstract: A method for forming ultra shallow junctions in a semiconductor wafer with reduced junction leakage arising from a silicidation process amorphizes the semiconductor material in the gate and source/drain junctions prior to the deposition of the metal during silicidation. After the gate and source/drain junctions are formed in a semiconductor device, non-dopant material, such as silicon or germanium, is implanted into the semiconductor material in an unmasked implantation procedure. This highly controllable implanting creates amorphous silicon regions with a substantially smooth interface with the crystalline silicon. When the silicide regions are formed during subsequent annealing steps, the silicide forms in a manner that follows the amorphous regions so that the silicide/silicon interface is also substantially smooth and junction leakage induced by silicidation is prevented.

Abstract: A method is provided for fabricating a semiconductor device on a structure, the method including forming a dielectric layer adjacent a gate conductor of the semiconductor device and above an LDD region of the structure and forming a first dielectric spacer adjacent a first portion of the dielectric layer adjacent the gate conductor and above a second portion of the dielectric layer above the LDD region. The method also includes introducing a dopant into a source/drain region of the structure and removing a third portion of the dielectric layer above the gate conductor, the second portion of the dielectric layer above the LDD region, and the first dielectric spacer. In addition, the method includes forming a first conductive layer above the gate conductor, adjacent the first portion of the dielectric layer and above the LDD region, and saliciding the first conductive layer above the gate conductor and above the LDD region to form a salicided first conductive layer.

Abstract: A method is provided for fabricating a semiconductor device on a structure, the method including forming a dielectric layer adjacent a gate conductor of the semiconductor device and above an LDD region of the structure and removing a first portion of the dielectric layer above the gate conductor and above the LDD region. The method also includes forming a first conductive layer above the gate conductor, adjacent the dielectric layer and above the LDD region and saliciding the first conductive layer above the gate conductor and above the LDD region to form a salicided first conductive layer.

Abstract: High integrity shallow source/drain junctions are formed employing cobalt silicide contacts. A layer of cobalt and a cap layer of titanium or titanium nitride are deposited on a substrate above intended source/drain regions, followed by silicidation. Embodiments include low-temperature rapid thermal annealing to form a high-resistivity phase cobalt silicide, removing the cap layer, depositing a doped film on the first phase cobalt silicide, and heating, as by high-temperature rapid thermal annealing, to form a low-resistance cobalt silicide during which impurities from the doped film diffuse through the cobalt silicide into the substrate to form source/drain regions having junctions extending into the substrate a constant depth below the cobalt silicide/silicon substrate interface. In another embodiment, impurities are diffused from the doped film to form source/drain regions and self-aligned junctions following formation of the low-resistance phase cobalt silicide.

Abstract: A semiconductor device includes a substrate, a gate structure, a plurality of sidewall spacers, and a plurality of first silicide layers. The gate structure is positioned above the substrate. The plurality of sidewall spacers are positioned adjacent to the gate structure. The first silicide layers are positioned in the substrate and have first ends that extend underneath the sidewall spacers. A method for forming a semiconductor device includes forming a gate structure above a substrate. A plurality of sidewall spacers are formed adjacent the gate structure. An implant material is disposed into the substrate using a tilted implantation process that is adapted to form first implant regions in the substrate. The implant regions have first ends that extend underneath the sidewall spacers by a first distance.

Abstract: Methods of fabricating a silicide layer on a substrate or transistor structures thereon are provided. An exemplary method includes the steps of depositing a layer of metal on a substrate that has a pn junction. The metal layer and the substrate are heated to react the metal with the substrate and form the silicide layer. Any unreacted metal is removed. The substrate and the silicide layer are heated above the agglomeration threshold temperature of any filaments of the silicide layer penetrating the pn junction but below the agglomeration threshold temperature of the silicide layer. The method eliminates silicide filaments, particularly in cobalt silicide processing, that can otherwise penetrate the pn junction of a transistor source/drain region a lead to reverse-bias diode-leakage currents.

Abstract: A method of forming metal silicide in a semiconductor wafer with reduced junction leakage introduces an alloy at cobalt grain boundaries within a cobalt layer that overlays a silicon layer. The alloy element can be precipitated during deposition of the cobalt and the alloy element, or by an intermediate anneal after deposition. The cobalt layer and the silicon layer are then annealed to form metal silicide regions. By precipitating an alloy at the cobalt grain boundaries, cobalt diffusion at the grain boundaries is retarded during a first rapid thermal annealing step. Bulk diffusion is encouraged, and a more uniform silicide film with reduced interface roughness is produced. Since the interface roughness is reduced with the methods of the present invention, junction leakage is reduced. This allows shallower junctions to be fabricated, leading to devices with improved performance.

Abstract: High integrity ultra-shallow source/drain junctions are formed employing cobalt silicide contacts. These are formed by depositing a layer of cobalt on a substrate above intended source/drain regions, and depositing a doped amorphous silicon film on the cobalt. Silicidation, as by rapid thermal annealing, is performed to form a low-resistance cobalt suicide while consuming the amorphous silicon film and diffusing impurities from the doped amorphous silicon film through the cobalt silicide into the substrate. The diffusion of the impurities forms shallow junctions extending into the substrate a substantially constant depth below the cobalt silicide/silicon substrate interface.

Abstract: A method for forming ultra shallow junctions in a semiconductor wafer with reduced silicon consumption during salicidation supplies additional silicon during the salicidation process. After the gate and source/drain junctions are formed in a semiconductor device, high resistivity metal silicide regions are formed on the gate and source/drain junctions. Silicon is then deposited in a layer on the high resistivity metal silicide regions. An annealing step is then performed to form low resistivity metal silicide regions on the gate and source/drain junctions. The deposited silicon is a source of silicon that is employed as a diffusion species during the transformation of the high resistivity metal silicide (such as CoSi) to a low resistivity metal silicide (such as CoSi.sub.2).

Abstract: High integrity ultra-shallow source/drain junctions are formed employing cobalt silicide contacts. Emdodiments include forming field oxide regions, gates, spacers, and lightly doped implants, and then depositing a layer of oxide on a substrate. The oxide layer is masked to protect portions of the oxide layer located near the gate, where it is desired to have a shallow junction, then etched to expose portions of the intended source/drain regions where the silicided contacts are to be formed. A high-dosage source/drain implant is thereafter carried out to form deep source/drain junctions with the substrate where the oxide layer has been etched away, and to form shallower junctions near the gates, where the implant must travel through the oxide layer before reaching the substrate. A layer of cobalt is thereafter deposited and silicidation is performed to form metal silicide contacts over only the deep source/drain junctions, while the cobalt on the oxide layer (i.e.

Abstract: Self-aligned, ultra-shallow, heavily-doped source and drain regions of a MOS device are formed by implanting dopant containing ions in a dielectric layer formed on metal silicide layer portions on regions of a silicon-containing substrate where source and drain regions are to be formed in a silicon-containing substrate. Thermal treatment of the implanted dielectric layer results in out-diffusion of dopant through the metal silicide layer and into the region of the silicon-containing substrate immediately below the metal silicide layer portions, thereby forming heavily doped source and drain regions having an ultra-shallow junction spaced apart from the metal silicide/silicon substrate interface by a substantially uniform distance.

Abstract: Various methods of fabricating a silicide layer, and devices incorporating the same are provided. In one aspect, a method of fabricating a silicide layer on a substrate is provided. The method includes the steps of damaging the crystal structure of a portion of the substrate positioned beneath the spacer and depositing a layer of metal on the substrate. The metal layer and the substrate are heated to react the metal with the substrate and form the silicide layer, whereby a portion of the silicide layer extends laterally beneath the spacer. Any unreacted metal is removed. The method enables fabrication of silicide layers with substantial lateral encroachment into LDD structures, resulting in lower possible source-to-drain resistance and enhanced performance for transistors.

Abstract: An integrated circuit fabrication process and transistor is provided in which salicidation is virtually eliminated from the spacer sidewall surface. Absent salicidation on that surface, bridging effects cannot occur regardless of the anneal conditions. The spacer sidewall surfaces is made substantially perpendicular to the substrate upper surface such that when a refractory metal is subsequently deposited on the semiconductor topography, the refractory metal will not accumulate on that perpendicular surface. The spacer is deposited from a specifically designed plasma enhanced chemical vapor deposition process to maintain the spacer sidewall surfaces commensurate with the gate conductor sidewall surfaces. The refractory metal is directionally deposited so that little if any metal will form on vertical surfaces and substantially all of the metal will deposit on horizontal surfaces.

Abstract: High integrity ultra-shallow source/drain junctions are formed employing cobalt silicide contacts. Field oxide regions, gates, spacers, and source/drain implants are initially formed. A layer of silicon is then deposited. A protective non-contuctive film is then formed and anisotropically etched to expose the silicon layer on the source/drain regions and the top surfaces of the gates, and to form protective spacers on the edges of the field oxide regions and on the side surfaces of the gates. A layer of cobalt is thereafter deposited and silicidation is performed, as by rapid thermal annealing, to form a low-resistance cobalt silicide while consuming the silicon film. The consumption of the silicon film during silicidation results in less consumption of substrate silicon, thereby enabling the formation of ultra-shallow source/drain junctions without junction leakage, allowing the formation of cobalt silicide contacts at optimum thickness and facilitating reliable device scaling.

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.