Abstract:
A method for making a semiconductor device includes forming at least one gate stack on a layer comprising a first semiconductor material and etching source and drain recesses adjacent the at least one gate stack. The method further includes shaping the source and drain recesses to have a vertical side extending upwardly from a bottom to an inclined extension adjacent the at least one gate stack.
Abstract:
Methods and structures for forming localized, differently-strained regions in a semiconductor layer on a substrate are described. An initial, unstrained, semiconductor-on-insulator substrate may be processed to form the differently-strained regions in the original semiconductor layer. The differently-strained regions may have opposite types of strain. The strains in the different regions may be formed independently.
Abstract:
One illustrative method disclosed herein involves, among other things, forming trenches to form an initial fin structure having an initial exposed height and sidewalls, forming a protection layer on at least the sidewalls of the initial fin structure, extending the depth of the trenches to thereby define an increased-height fin structure, with a layer of insulating material over-filling the final trenches and with the protection layer in position, performing a fin oxidation thermal anneal process to convert at least a portion of the increased-height fin structure into an isolation material, removing the protection layer, and performing an epitaxial deposition process to form a layer of semiconductor material on at least portions of the initial fin structure.
Abstract:
Methods and structures for forming a localized, strained region of a substrate are described. Trenches may be formed at boundaries of a localized region of a substrate. An upper portion of sidewalls at the localized region may be covered with a covering layer, and a lower portion of the sidewalls at the localized region may not be covered. A converting material may be formed in contact with the lower portion of the localized region, and the substrate heated. The heating may introduce a chemical species from the converting material into the lower portion, which creates stress in the localized region. The methods may be used to form strained-channel finFETs.
Abstract:
A transistor includes a body and a semiconductor region configured to stress a portion of the body. For example, stressing a channel of the transistor may increase the mobility of carriers in the channel, and thus may reduce the “on” resistance of the transistor. For example, the substrate, source/drain regions, or both the substrate and source/drain regions of a PFET may be doped to compressively stress the channel so as to increase the mobility of holes in the channel. Or, the substrate, source/drain regions, or both the substrate and source/drain regions of an NFET may be doped to tensile stress the channel so as to increase the mobility of electrons in the channel.
Abstract:
A method of making a semiconductor device includes forming an intermediate structure including second semiconductor fin portions above a first semiconductor layer, and top first semiconductor fin portions extending from respective ones of the second semiconductor fin portions. The second semiconductor fin portions are selectively etchable with respect to the top first semiconductor fin portions. A dummy gate is on the intermediate structure. The second semiconductor fin portions are selectively etched to define bottom openings under respective ones of the top first semiconductor fin portions. The bottom openings are filled with a dielectric material.
Abstract:
A memory device may include a semiconductor substrate, and a memory transistor in the semiconductor substrate. The memory transistor may include source and drain regions in the semiconductor substrate and a channel region therebetween, and a gate stack. The gate stack may include a first dielectric layer over the channel region, a first diffusion barrier layer over the first dielectric layer, a first electrically conductive layer over the first diffusion barrier layer, a second dielectric layer over the first electrically conductive layer, a second diffusion barrier layer over the second dielectric layer, and a second electrically conductive layer over the second diffusion barrier layer. The first and second dielectric layers may include different dielectric materials, and the first diffusion barrier layer may be thinner than the second diffusion barrier layer.
Abstract:
Methods and structures for forming strained-channel finFETs are described. Fin structures for finFETs may be formed in two epitaxial layers that are grown over a bulk substrate. A first thin epitaxial layer may be cut and used to impart strain to an adjacent channel region of the finFET via elastic relaxation. The structures exhibit a preferred design range for increasing induced strain and uniformity of the strain over the fin height.
Abstract:
A memory device may include a semiconductor substrate, and a memory transistor in the semiconductor substrate. The memory transistor may include source and drain regions in the semiconductor substrate and a channel region therebetween, and a gate stack having a first dielectric layer over the channel region, a second dielectric layer over the first dielectric layer, a first diffusion barrier layer over the second dielectric layer, a first electrically conductive layer over the first diffusion barrier layer, a second diffusion barrier layer over the first electrically conductive layer, and a second electrically conductive layer over the second diffusion barrier layer. The first and second dielectric layers may include different dielectric materials, and the first diffusion barrier layer may be thinner than the second diffusion barrier layer.
Abstract:
Despite improvements in FinFETs and strained silicon devices, transistors continue to suffer performance degradation as device dimensions shrink. These include, in particular, leakage of charge between the semiconducting channel and the substrate. An isolated channel FinFET device prevents channel-to-substrate leakage by inserting an insulating layer between the channel (fin) and the substrate. The insulating layer isolates the fin from the substrate both physically and electrically. To form the isolated FinFET device, an array of bi-layer fins can be grown epitaxially from the silicon surface, between nitride columns that provide localized insulation between adjacent fins. Then, the lower fin layer can be removed, while leaving the upper fin layer, thus yielding an interdigitated array of nitride columns and semiconducting fins suspended above the silicon surface. A resulting gap underneath the upper fin layer can then be filled in with oxide to isolate the array of fin channels from the substrate.