Abstract: A semiconductor fabrication process includes forming a transistor gate overlying an SOI wafer having a semiconductor top layer over a buried oxide layer (BOX) over a semiconductor substrate. Source/drain trenches, disposed on either side of the gate, are etched into the BOX layer. Source/drain structures are formed within the trenches. A depth of the source/drain structures is greater than the thickness of the top silicon layer and an upper surface of the source/drain structures coincides approximately with the transistor channel whereby vertical overlap between the source/drain structures and the gate is negligible. The trenches preferably extend through the BOX layer to expose a portion of the silicon substrate. The source/drain structures are preferably formed epitaxially and possibly in two stages including an oxygen rich stage and an oxygen free stage. A thermally anneal between the two epitaxial stages will form an isolation dielectric between the source/drain structure and the substrate.

Abstract: A vacancy injecting process for injecting vacancies in template layer material of an SOI substrate. The template layer material has a crystalline structure that includes, in some embodiments, both germanium and silicon atoms. A strained silicon layer is then epitaxially grown on the template layer material with the beneficial effects that straining has on electron and hole mobility. The vacancy injecting process is performed to inject vacancies and germanium atoms into the crystalline structure wherein germanium atoms recombine with the vacancies. One embodiment, a nitridation process is performed to grow a nitride layer on the template layer material and consume silicon in a way that injects vacancies in the crystalline structure while also allowing germanium atoms to recombine with the vacancies.

Abstract: A transistor is formed using a semiconductor substrate and forming a control electrode overlying the semiconductor substrate. A first current electrode is formed within the semiconductor substrate and adjacent the control electrode. The first current electrode has a first predetermined semiconductor material. A second current electrode is formed within the semiconductor substrate and adjacent the control electrode to form a channel within the semiconductor substrate. The second current electrode has a second predetermined semiconductor material that is different from the first predetermined semiconductor material. The first predetermined semiconductor material is chosen to optimize bandgap energy of the first current electrode, and the second predetermined semiconductor material is chosen to optimize strain of the channel.

Abstract: A semiconductor device (10) is formed by positioning a gate (22) overlying a semiconductor layer (16) of preferably silicon. A semiconductor material (26) of, for example only, SiGe or Ge, is formed adjacent the gate over the semiconductor layer and over source/drain regions. A thermal process diffuses the stressor material into the semiconductor layer. Lateral diffusion occurs to cause the formation of a strained channel (17) in which a stressor material layer (30) is immediately adjacent the strained channel. Extension implants create source and drain implants from a first portion of the stressor material layer. A second portion of the stressor material layer remains in the channel between the strained channel and the source and drain implants. A heterojunction is therefore formed in the strained channel. In another form, oxidation of the stressor material occurs rather than extension implants to form the strained channel.

Abstract: A semiconductor device (10) is formed by positioning a gate (22) overlying a semiconductor layer (16) of preferably silicon. A semiconductor material (26) of, for example only, SiGe or Ge, is formed adjacent the gate over the semiconductor layer and over source/drain regions. A thermal process diffuses the stressor material into the semiconductor layer. Lateral diffusion occurs to cause the formation of a strained channel (17) in which a stressor material layer (30) is immediately adjacent the strained channel. Extension implants create source and drain implants from a first portion of the stressor material layer. A second portion of the stressor material layer remains in the channel between the strained channel and the source and drain implants. A heterojunction is therefore formed in the strained channel. In another form, oxidation of the stressor material occurs rather than extension implants to form the strained channel.

Abstract: A semiconductor device (10) is formed by positioning a gate (22) overlying a semiconductor layer (16) of preferably silicon. A semiconductor material (26) of, for example only, SiGe or Ge, is formed adjacent the gate over the semiconductor layer and over source/drain regions. A thermal process diffuses the stressor material into the semiconductor layer. Lateral diffusion occurs to cause the formation of a strained channel (17) in which a stressor material layer (30) is immediately adjacent the strained channel. Extension implants create source and drain implants from a first portion of the stressor material layer. A second portion of the stressor material layer remains in the channel between the strained channel and the source and drain implants. A heterojunction is therefore formed in the strained channel. In another form, oxidation of the stressor material occurs rather than extension implants to form the strained channel.

Abstract: A semiconductor fabrication process includes forming a recess in a semiconductor substrate. A silicon germanium film is formed on a sidewall of the recess. A gate dielectric and gate electrode are formed adjacent the silicon germanium film. Source/drain regions are then formed wherein a first source/drain region is adjacent a first side of the gate electrode in an upper surface of the substrate and a second source/drain region adjacent a second side of the gate electrode is below a lower surface of the recess. Etching the exposed portion of the substrate may be done so as to form a rounded corner at the junction of the recess sidewall and the recess lower surface. The silicon germanium film formation is preferably epitaxial. An epitaxial silicon film may be formed adjacent the silicon germanium film.

Abstract: A metal layer is formed over a metal oxide, where the metal oxide is formed over a semiconductor substrate. A predetermined critical dimension of the metal layer is determined. A first etch is performed to etch the metal layer down to the metal oxide and form footings at the sidewalls of the metal layer. A second etch to remove the footings to target a predetermined critical dimension, wherein the second etch is selective to the metal oxide. In one embodiment, a conductive layer is formed over the metal layer. The bulk of the conductive layer may be etched leaving a portion in contact with the metal layer. Next, the portion left in contact with the metal layer may be etched using chemistry selective to the metal layer.

Abstract: A process for forming a semiconductor device. The process includes forming a template layer for forming a layer of strained silicon. In one example a layer of graded silicon germanium is formed where the germanium is at a higher concentration at the lower portion and at a lower concentration at a top portion. When subject to a condensation process, the germanium of the top portion of the layer diffuses to a remaining portion of the silicon germanium layer. Because the silicon germanium layer has a higher concentration of germanium at lower portions, germanium pile up after condensation may be reduced at the upper portion of the remaining portion of the silicon germanium layer.

Abstract: A method for forming at least a portion of a semiconductor device includes providing a substrate and epitaxially forming an etch stop layer over the substrate. A first layer is provided over the etch stop layer, wherein the first layer is selectively etchable with regard to the etch stop layer. A structure is provided over a region of the first layer, wherein the region is not all of the first layer. In addition, the method includes etching at least a portion of the first layer that is outside of the region, wherein the etch stop layer is used an as etch stop. A strained layer is epitaxially grown in the etch-recessed region.

Abstract: A transistor is formed using a semiconductor substrate and forming a control electrode overlying the semiconductor substrate. A first current electrode is formed within the semiconductor substrate and adjacent the control electrode. The first current electrode has a first predetermined semiconductor material. A second current electrode is formed within the semiconductor substrate and adjacent the control electrode to form a channel within the semiconductor substrate. The second current electrode has a second predetermined semiconductor material that is different from the first predetermined semiconductor material. The first predetermined semiconductor material is chosen to optimize bandgap energy of the first current electrode, and the second predetermined semiconductor material is chosen to optimize strain of the channel.

Abstract: A semiconductor fabrication process includes forming a silicon fin overlying a substrate. A gate dielectric is formed on primary faces of the fin. A gate electrode is formed over at least two faces of the fin. Dielectric spacers are then selectively formed in close proximity and confined to the sidewalls of the gate electrode thereby leaving a majority of the primary fin faces exposed. Thereafter a silicide is formed on the primary fin faces. The forming of the gate electrode in one embodiment includes depositing polysilicon over the fin and substrate, depositing a capping layer over the polysilicon, patterning photoresist over the capping layer and etching through the capping layer and the polysilicon with the patterned photoresist in place wherein the etching produces a polysilicon width that is less than a width of the capping layer to create voids under the capping layer adjacent sidewalls of the polysilicon where the confined spacers can be formed.

Abstract: A method for providing gates of transistors with at least two different work functions utilizes a silicidation of two different metals at different times, silicidation for one gate and polysilicon for the other, or silicidation using a single metal with two differently doped silicon structures. Thus the problem associated with performing silicidation of two different metals at the same time is avoided. If the two metals have significantly different silicidation temperatures, the one with the lower temperature silicidation will likely have significantly degraded performance as a result of having to also experience the higher temperature required to achieve silicidation with the other metal.

Abstract: A first semiconductor structure has a silicon substrate, a first silicon germanium layer grown on the silicon, a second silicon germanium layer on the first silicon germanium layer, and a strained silicon layer on the second silicon germanium layer. A second semiconductor structure has a silicon substrate and an insulating top layer. The silicon layer of the first semiconductor structure is bonded to the insulator layer to form a third semiconductor structure. The second silicon germanium layer is cut to separate most of the first semiconductor structure from the third semiconductor structure. The silicon germanium layer is removed to expose the strained silicon layer where transistors are subsequently formed, which is then the only layer remaining from the first semiconductor structure. The transistors are oriented along the <100> direction and at a 45 degree angle to the <100> direction of the base silicon layer of the second silicon.

Abstract: A semiconductor fabrication process includes forming a silicon fin overlying a substrate. A gate dielectric is formed on primary faces of the fin. A gate electrode is formed over at least two faces of the fin. Dielectric spacers are then selectively formed in close proximity and confined to the sidewalls of the gate electrode thereby leaving a majority of the primary fin faces exposed. Thereafter a silicide is formed on the primary fin faces. The forming of the gate electrode in one embodiment includes depositing polysilicon over the fin and substrate, depositing a capping layer over the polysilicon, patterning photoresist over the capping layer and etching through the capping layer and the polysilicon with the patterned photoresist in place wherein the etching produces a polysilicon width that is less than a width of the capping layer to create voids under the capping layer adjacent sidewalls of the polysilicon where the confined spacers can be formed.

Abstract: A method of forming a semiconductor device so as to provide the device inverted isolation trenches with convex sidewalls. Initially, a plurality of composite isolation posts (50, 51) are formed on a substrate (40) through successive deposition, lithography, and etching steps. The posts comprise a bottom layer (501, 502) of silicon dioxide and an overlying etch-stop layer of silicon nitride (502, 512). An insulating material (60) is then deposited over the isolation posts and areas of the substrate. Isolation structures (70,71) are established by etching the insulating material to form convex sidewall spacers (701,702, 711, 712) at the vertical walls of the isolation posts. Active areas (80) between spacers are filled with semiconductor material. In an embodiment, a strained cap layer (101) may be imposed on the active areas. The strained cap layer has a lattice constant that is different from the lattice constant of the semiconductor material.

Abstract: A process for forming a strained semiconductor layer. The process includes implanting ions into a semiconductor layer prior to performing a condensation process on the layer. The ions assist in diffusion of atoms (e.g. germanium) in the semiconductor layer and to increase the relaxation of the semiconductor layer. After the condensation process, the layer can be used as a template layer for forming a strained semiconductor layer.

Abstract: A process for forming strained semiconductor layers. The process include flowing a chlorine bearing gas (e.g. hydrogen chloride, chlorine, carbon tetrachloride, and trichloroethane) over the wafer while heating the wafer. In one example, the chorine bearing gas is flowed during a condensation process on a semiconductor layer that is used as a template layer for forming a strain semiconductor layer (e.g. strain silicon). In other examples, the chlorine bearing gas is flowed during a post bake of the wafer after the condensation operation.

Abstract: A vacancy injecting process for injecting vacancies in template layer material of an SOI substrate. The template layer material has a crystalline structure that includes, in some embodiments, both germanium and silicon atoms. A strained silicon layer is then epitaxially grown on the template layer material with the beneficial effects that straining has on electron and hole mobility. The vacancy injecting process is performed to inject vacancies and germanium atoms into the crystalline structure wherein germanium atoms recombine with the vacancies. One embodiment, a nitridation process is performed to grow a nitride layer on the template layer material and consume silicon in a way that injects vacancies in the crystalline structure while also allowing germanium atoms to recombine with the vacancies.

Abstract: A method for forming a polysilicon FinFET (10) or other thin film transistor structure includes forming an insulative layer (12) over a semiconductor substrate (14). An amorphous silicon layer (32) forms over the insulative layer (12). A silicon germanium seed layer (44) forms in association with the amorphous silicon layer (32) for controlling silicon grain growth. The polysilicon layer arises from annealing the amorphous silicon layer (32). During the annealing step, silicon germanium seed layer (44), together with silicon germanium layer (34), catalyzes silicon recrystallization to promote growing larger crystalline grains, as well as fewer grain boundaries within the resulting polysilicon layer. Source (16), drain (18), and channel (20) regions are formed within the polysilicon layer. A double-gated region (24) forms in association with source (16), drain (18), and channel (20) to produce polysilicon FinFET (10).