Title :
Examination of Additive Mobility Enhancements for Uniaxial Stress Combined with Biaxially Strained Si, Biaxially Strained SiGe and Ge Channel MOSFETs
Author :
Weber, O. ; Irisawa, T. ; Numata, T. ; Harada, M. ; Taoka, N. ; Yamashita, Y. ; Yamamoto, T. ; Sugiyama, N. ; Takenaka, M. ; Takagi, S.
Author_Institution :
Univ. of Tokyo, Tokyo
Abstract :
Uniaxial and biaxial strain additive mobility enhancements and their physical understandings are experimentally examined by applying mechanical stress to high mobility channel materials. As for nMOSFETs, <110> uniaxial and biaxial tensile strain are partially additive in the electron mobility enhancement due to the conduction band warping and resulting effective mass reduction under shear strain. As for pMOSFETs, it is found that an initial compressive biaxial strain is efficient to boost the impact of the shear strain component in the <110> uniaxial strain on hole mobility, demonstrating the effectiveness in combining uniaxial and biaxial stress for strained SiGe channels. The piezoresistance coefficients for (001) Germanium pMOSFETs are also experimentally evaluated for the first time.
Keywords :
Ge-Si alloys; MOSFET; compressive strength; conduction bands; effective mass; electron mobility; germanium; hole mobility; piezoresistance; tensile strength; Ge; MOSFET; Si-Ge; additive mobility enhancement; biaxial strain; compressive strain; conduction band; effective mass reduction; electron mobility enhancement; hole mobility; mechanical stress; mobility channel materials; piezoresistance coefficient; shear strain; tensile strain; uniaxial stress; Additives; Conducting materials; Effective mass; Electron mobility; Germanium silicon alloys; MOSFETs; Silicon germanium; Tensile strain; Tensile stress; Uniaxial strain;
Conference_Titel :
Electron Devices Meeting, 2007. IEDM 2007. IEEE International
Conference_Location :
Washington, DC
Print_ISBN :
978-1-4244-1507-6
Electronic_ISBN :
978-1-4244-1508-3
DOI :
10.1109/IEDM.2007.4419047
