Mie Fujitsu Semiconductor Limited

Suvolta, Inc.

Lingquan Wang

Pushkar Ranade

Dalong Zhao

Teymur Bakhishev

Scott E Thompson

Sameer S Pradhan

Lucian Shifren

Thomas Hoffmann

Lance A Scudder

Sung Hwan Kim

Michael Duane

Yujie Liu

Weimin Zhang

Jing Wang

Sachin R Sonkusale

Paul E Gregory

Semiconductor devices and methods of fabricating such devices are provided. The devices include source and drain regions on one conductivity type separated by a channel length and a gate structure. The devices also include a channel region of the one conductivity type formed in the device region between the source and drain regions and a screening region of another conductivity type formed below the channel region and between the source and drain regions. In operation, the channel region forms, in response to a bias voltage at the gate structure, a surface depletion region below the gate structure, a buried depletion region at an interface of the channel region and the screening region, and a buried channel region between the surface depletion region and the buried depletion region, where the buried depletion region is substantially located in channel region.

Buried channel deeply depleted channel transistor

A transistor and method of fabrication thereof includes a screening layer formed at least in part in the semiconductor substrate beneath a channel layer and a gate stack, the gate stack including spacer structures on either side of the gate stack. The transistor includes a shallow lightly doped drain region in the channel layer and a deeply lightly doped drain region at the depth relative to the bottom of the screening layer for reducing junction leakage current. A compensation layer may also be included to prevent loss of back gate control.

Method for fabricating a transistor with reduced junction leakage current

High uniformity screen and epitaxial layers for CMOS devices

A method of fabricating a semiconductor device includes providing a substrate having a semiconducting surface and forming a first epitaxial layer on the semiconducting surface. The first epitaxial layer includes a first semiconducting material doped in-situ with at least one dopant of a first conductivity type. The method also includes adding at least one dopant of a second conductivity type into one portion of the substrate to define at least one counter-doped region with an overall doping of the second conductivity type and at least one other region with an overall doping of the first conductivity type in the other portions of substrate. The method further includes forming a second epitaxial layer on the first epitaxial layer, the second epitaxial layer being a second semiconducting material that is substantially undoped.

Semiconductor devices with dopant migration suppression and method of fabrication thereof

A semiconductor structure is formed with a NFET device and a PFET device. The NFET device is formed by masking the PFET device regions of a substrate, forming a screen layer through epitaxial growth and in-situ doping, and forming an undoped channel layer on the screen layer through epitaxial growth. The PFET device is similarly formed by masking the NFET regions of a substrate, forming a screen layer through epitaxial growth and in-situ doping, and forming an undoped channel layer on the screen layer through epitaxial growth. An isolation region is formed between the NFET and the PFET device areas to remove any facets occurring during the separate epitaxial growth phases. By forming the screen layer through in-situ doped epitaxial growth, a reduction in junction leakage is achieved versus forming the screen layer using ion implantation.

Semiconductor structure with reduced junction leakage and method of fabrication thereof

A semiconductor transistor structure fabricated on a silicon substrate effective to set a threshold voltage, control short channel effects, and control against excessive junction leakage may include a transistor gate having a source and drain structure. A highly doped screening region lies is embedded a vertical distance down from the surface of the substrate. The highly doped screening region is separated from the surface of the substrate by way of a substantially undoped channel layer which may be epitaxially formed. The source/drain structure may include a source/drain extension region which may be raised above the surface of the substrate. The screening region is preferably positioned to be located at or just below the interface between the source/drain region and source/drain extension portion. The transistor gate may be formed below a surface level of the silicon substrate and either above or below the heavily doped portion of the source/drain structure.

Deeply depleted MOS transistors having a screening layer and methods thereof

Transistor having reduced junction leakage and methods of forming thereof

A semiconductor structure is formed with a NFET device and a PFET device. The NFET device is formed by masking the PFET device regions of a substrate, forming a screen layer through epitaxial growth and in-situ doping, and forming an undoped channel layer on the screen layer through epitaxial growth. The PFET device is similarly formed by masking the NFET regions of a substrate, forming a screen layer through epitaxial growth and in-situ doping, and forming an undoped channel layer on the screen layer through epitaxial growth. An isolation region is formed between the NFET and the PFET device areas to remove any facets occurring during the separate epitaxial growth phases. By forming the screen layer through in-situ doped epitaxial growth, a reduction in junction leakage is achieved versus forming the screen layer using ion, implantation.

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Irvine, CA, United States of America

Lingquan Wang