Strained-silicon CMOS device and method

Abstract

The present invention provides a semiconductor device and a method of forming thereof, in which a uniaxial strain is produced in the device channel of the semiconductor device. The uniaxial strain may be in tension or in compression and is in a direction parallel to the device channel. The uniaxial strain can be produced in a biaxially strained substrate surface by strain inducing liners, strain inducing wells or a combination thereof. The uniaxial strain may be produced in a relaxed substrate by the combination of strain inducing wells and a strain inducing liner. The present invention also provides a means for increasing biaxial strain with strain inducing isolation regions. The present invention further provides CMOS devices in which the device regions of the CMOS substrate may be independently processed to provide uniaxially strained semiconducting surfaces in compression or tension.

Description

RELATED APPLICATION[0001]This application is a divisional of U.S. application Ser. No. 11 / 619,511 filed on Jan. 3, 2007, which is a divisional of U.S. application Ser. No. 10 / 930,404 filed Aug. 31, 2004, now U.S. Pat. No. 7,227,205 issued on Jun. 5, 2007.CROSS REFERENCE TO RELATED APPLICATION[0002]The present invention claims benefit of U.S. provisional patent application 60 / 582,678 filed Jun. 24, 2004, the entire content and disclosure of which is incorporated by reference.FIELD OF THE INVENTION[0003]The present invention relates to semiconductor devices having enhanced electron and hole mobilities, and more particularly, to semiconductor devices that include a silicon (Si)-containing layer having enhanced electron and hole mobilities. The present invention also provides methods for forming such semiconductor devices.BACKGROUND OF THE INVENTION[0004]For more than three decades, the continued miniaturization of silicon metal oxide semiconductor field effect transistors (MOSFETs) has...

AI Technical Summary

Benefits of technology

The present invention provides a strained nFET device with improved carrier mobility in the device channel by inducing uniaxial strain in a direction parallel to the device channel. The strain can be achieved by inducing a strain in the semiconducting surface using a strain inducing layer or by inducing a uniaxial strain in the device channel through a strain inducing liner. The invention also provides a strained pFET device with improved carrier mobility by inducing uniaxial compressive strain in a direction parallel to the device channel. A complementary metal oxide semiconducting (CMOS) structure including both nFET and pFET devices can also be provided. The technical effects of the invention include improved performance and reliability of semiconductor devices.

Problems solved by technology

However, there are growing signs today that metal oxide semiconductor transistors are beginning to reach their traditional scaling limits.

Since it has become increasingly difficult to improve MOSFETs and therefore CMOS performance through continued scaling, methods for improving performance without scaling have become critical.

This results in changes in carrier transport properties, which can be dramatic in certain cases.

It is believed that the reduction in drive currents in very short channel devices results from source / drain series resistance and that mobility degradation is due to higher channel doping by strong halo doping, velocity saturation, and self-heating.

In addition, in the case of biaxial tensile strain, such as strained epitaxially grown Si on relaxed SiGe, significant hole mobility enhancement for pFET devices only occurs when the device channel is under a high (>1%) strain, which is disadvantageously prone to have crystalline defects.

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