Abstract:
An improved transistor with channel epitaxial silicon and methods for fabrication thereof. In one aspect, a method for fabricating a transistor includes: forming a gate stack structure on an epitaxial silicon region, a width dimension of the epitaxial silicon region approximating a width dimension of the gate stack structure; encapsulating the epitaxial silicon region under the gate stack structure with sacrificial spacers formed on both sides of the gate stack structure and the epitaxial silicon region; forming a channel of the transistor having a width dimension that approximates that of the epitaxial silicon region and the gate stack structure, the epitaxial silicon region and the gate stack structure formed on the channel of the transistor; removing the sacrificial spacers; and growing a raised epitaxial source and drain from the silicon substrate, with portions of the raised epitaxial source and drain in contact with the epitaxial silicon region.
Abstract:
On a substrate formed of a first semiconductor material, a first overlying layer formed of a second semiconductor material is deposited. A second overlying layer formed of a third semiconductor material is deposited over the first overlying layer. The first and second overlying layers are patterned to define fins, wherein each fin includes a first region formed of the third material over a second region formed of the second material. An oxide material fills the space between the fins. A thermal oxidation is then performed to convert the second region to a material insulating the first region formed of the third material from the substrate. As an optional step, the second region formed of the second material is horizontally thinned before the oxide material is deposited and the thermal oxidation is performed. Once the fins are formed and insulated from the substrate, conventional FinFET fabrication is performed.
Abstract:
Channel-to-substrate leakage in a FinFET device is prevented by inserting an insulating layer between the semiconducting channel (fin) and the substrate during fabrication of the device. Similarly, source/drain-to-substrate leakage in a FinFET device is prevented by isolating the source/drain regions from the substrate by inserting an insulating layer between the source/drain regions and the substrate. Forming such an insulating layer isolates the conduction path from the substrate both physically and electrically, thus preventing current leakage. In an array of semiconducting fins made up of a multi-layer stack, the bottom material is removed, thus yielding a fin array that is suspended above the silicon surface. A resulting gap underneath the remaining top fin material is then filled with oxide to better support the fins and to isolate the array of fins from the substrate.
Abstract:
An improved transistor with channel epitaxial silicon. In one aspect, a method of fabrication includes: forming a gate stack structure on an epitaxial silicon region disposed on a substrate, a width dimension of the epitaxial silicon region approximating a width dimension of the gate stack structure; and growing a raised epitaxial source and drain from the substrate, the raised epitaxial source and drain in contact with the epitaxial silicon region and the gate stack structure. For a SRAM device, further: removing an epitaxial layer in contact with the silicon substrate and the raised source and drain and to which the epitaxial silicon region is coupled leaving a space above the silicon substrate and under the raised epitaxial source and drain; and filling the space with an insulating layer and isolating the raised epitaxial source and drain and a channel of the transistor from the silicon substrate.
Abstract:
Channel-to-substrate leakage in a FinFET device can be prevented by inserting an insulating layer between the semiconducting channel (fin) and the substrate. Similarly, source/drain-to-substrate leakage in a FinFET device can be prevented by isolating the source/drain regions from the substrate by inserting an insulating layer between the source/drain regions and the substrate. The insulating layer isolates the conduction path from the substrate both physically and electrically, thus preventing current leakage. If an array of semiconducting fins is made up of a multi-layer stack, the bottom material can be removed thus yielding a fin array that is suspended above the silicon surface. A resulting gap underneath the remaining top fin material can then be filled in with oxide to better support the fins and to isolate the array of fins from the substrate. The resulting FinFET device is fully substrate-isolated in both the gate region and the source/drain regions.
Abstract:
The presence of a facet or a void in an epitaxially grown crystal indicates that crystal growth has been interrupted by defects or by certain material boundaries. Faceting can be suppressed during epitaxial growth of silicon compounds that form source and drain regions of strained silicon transistors. It has been observed that faceting can occur when epitaxial layers of certain silicon compounds are grown adjacent to an oxide boundary, but faceting does not occur when the epitaxial layer is grown adjacent to a silicon boundary or adjacent to a nitride boundary. Because epitaxial growth of silicon compounds is often necessary in the vicinity of isolation trenches that are filled with oxide, techniques for suppression of faceting in these areas are of particular interest. One such technique, presented herein, is to line the isolation trenches with SiN to provide a barrier between the oxide and the region in which epitaxial growth is intended.
Abstract:
A multi-fin FINFET device may include a substrate and a plurality of semiconductor fins extending upwardly from the substrate and being spaced apart along the substrate. Each semiconductor fin may have opposing first and second ends and a medial portion therebetween, and outermost fins of the plurality of semiconductor fins may comprise an epitaxial growth barrier on outside surfaces thereof. The FINFET may further include at least one gate overlying the medial portions of the semiconductor fins, a plurality of raised epitaxial semiconductor source regions between the semiconductor fins adjacent the first ends thereof, and a plurality of raised epitaxial semiconductor drain regions between the semiconductor fins adjacent the second ends thereof.
Abstract:
A method of making a semiconductor device includes forming a fin mask layer on a semiconductor layer, forming a dummy gate over the fin mask layer, and forming source and drain regions on opposite sides of the dummy gate. The dummy gate is removed and the underlying fin mask layer is used to define a plurality of fins in the semiconductor layer. A gate is formed over the plurality of fins.
Abstract:
A method for co-integrating finFETs of two semiconductor material types, e.g., Si and SiGe, on a bulk substrate is described. Fins for finFETs may be formed in an epitaxial layer of a first semiconductor type, and covered with an insulator. A portion of the fins may be removed to form voids in the insulator, and the voids may be filled by epitaxially growing a semiconductor material of a second type in the voids. The co-integrated finFETs may be formed at a same device level.
Abstract:
Channel-to-substrate leakage in a FinFET device can be prevented by inserting an insulating layer between the semiconducting channel and the substrate. Similarly, source/drain-to-substrate leakage in a FinFET device can be prevented by isolating the source/drain regions from the substrate by inserting an insulating layer between the source/drain regions and the substrate. The insulating layer isolates the conduction path from the substrate both physically and electrically, thus preventing current leakage. If an array of semiconducting fins is made up of a multi-layer stack, the bottom material can be removed thus yielding a fin array that is suspended above the silicon surface. A resulting gap underneath the remaining top fin material can then be filled in with oxide to better support the fins and to isolate the array of fins from the substrate. The resulting FinFET device is fully substrate-isolated in both the gate region and the source/drain regions.