Mie Fujitsu Semiconductor Limited

Suvolta, Inc.

Paul E Gregory

Lucian Shifren

Pushkar Ranade

Scott E Thompson

Lance A Scudder

Thomas Hoffmann

Dalong Zhao

Michael Duane

Weimin Zhang

Teymur Bakhishev

Sachin R Sonkusale

U C Sridharan

Sameer S Pradhan

Sung Hwan Kim

Jing Wang

Lingquan Wang

Urupattur C Sridharan

Yujie Liu

An advanced transistor with punch through suppression includes a gate with length Lg, a well doped to have a first concentration of a dopant, and a screening region positioned under the gate and having a second concentration of dopant. The second concentration of dopant may be greater than 5&#xd7;10dopant atoms per cm. At least one punch through suppression region is disposed under the gate between the screening region and the well. The punch through suppression region has a third concentration of a dopant intermediate between the first concentration and the second concentration of dopant. A bias voltage may be applied to the well region to adjust a threshold voltage of the transistor.

Advanced transistors with punch through suppression

A semiconductor structure includes first, second, and third transistor elements each having a first screening region concurrently formed therein. A second screening region is formed in the second and third transistor elements such that there is at least one characteristic of the screening region in the second transistor element that is different than the second screening region in the third transistor element. Different characteristics include doping concentration and depth of implant. In addition, a different characteristic may be achieved by concurrently implanting the second screening region in the second and third transistor element followed by implanting an additional dopant into the second screening region of the third transistor element.

Semiconductor structure with multiple transistors having various threshold voltages

Methods for fabricating semiconductor devices and devices therefrom are provided. A method includes providing a substrate having a semiconducting surface with first and second layers, where the semiconducting surface has a plurality of active regions comprising first and second active regions. In the first active region, the first layer is an undoped layer and the second layer is a highly doped screening layer. The method also includes removing a part of the first layer to reduce a thickness of the substantially undoped layer for at least a portion of the first active region without a corresponding thickness reduction of the first layer in the second active region. The method additionally includes forming semiconductor devices in the plurality of active regions. In the method, the part of the first layer removed is selected based on a threshold voltage adjustment required for the substrate in the portion of the first active region.

CMOS structures and processes based on selective thinning

A method for fabricating a semiconductor structure with a channel stack includes forming a screening layer under a gate of a PMOS transistor element and a NMOS transistor element, forming a threshold voltage control layer on the screening layer, and forming an epitaxial channel layer on the threshold control layer. At least a portion of the epitaxial channel layers for the PMOS transistor element and the NMOS transistor element are formed as a common blanket layer. The screening layer for the PMOS transistor element may include antimony as a dopant material that may be inserted into the structure prior to or after formation of the epitaxial channel layer.

Semiconductor structure with improved channel stack and method for fabrication thereof

An analog transistor useful for low noise applications or for electrical circuits benefiting from tight control of threshold voltages and electrical characteristics is described. The analog transistor includes a substantially undoped channel positioned under a gate dielectric between a source and a drain with the undoped channel not being subjected to contaminating threshold voltage implants or halo implants. The channel is supported on a screen layer doped to have an average dopant density at least five times as great as the average dopant density of the substantially undoped channel which, in turn, is supported by a doped well having an average dopant density at least twice the average dopant density of the substantially undoped channel.

Analog transistor

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

Process for manufacturing an improved analog transistor

Growing community of inventors

Palo Alto, CA, United States of America

Paul E Gregory