The effects of low-angle off-axis substrate orientation on MOSFET performance and reliability

Author

Chung, James E. ; Chen, Jian ; Ko, Ping-Keung ; Hu, Chenming ; Levi, Mark

Author_Institution

Dept. of Electr. Eng. & Comput. Sci., California Univ., Berkeley, CA, USA

Volume

38

Issue

3

fYear

1991

fDate

3/1/1991 12:00:00 AM

Firstpage

627

Lastpage

633

Abstract

The effects of low-angle off-axis substrate orientation on MOSFET performance and reliability are examined. When <100> wafers are tilted off axis from 0° to 8° around the <011> axis, two principal effects are observed. First, for current flow normal to the axis of rotation, inversion-layer mobility is lower than for current flow in the parallel direction. This mobility difference is due to anisotropy in the inversion-layer effective mass as well as increased surface roughness in the normal compared with the parallel direction. Second, as the substrate is rotated off axis, the susceptibility of gate oxide to defect-related breakdown is enhanced. The off-axis surface exhibits increased surface roughness, which promotes nonuniform oxidation and can significantly degrade VLSI reliability

Keywords

MOS integrated circuits; insulated gate field effect transistors; oxidation; reliability; semiconductor technology; <100> wafers; MOSFET performance; VLSI reliability degradation; current flow; defect-related breakdown; inversion-layer effective mass anisotropy; inversion-layer mobility; low-angle off-axis substrate orientation; mobility difference; nonuniform oxidation; off-axis surface; surface roughness; susceptibility of gate oxide; Anisotropic magnetoresistance; Fabrication; Gallium arsenide; MOSFET circuits; Oxidation; Rough surfaces; Silicon; Substrates; Surface roughness; Very large scale integration;

fLanguage

English

Journal_Title

Electron Devices, IEEE Transactions on

Publisher

ieee

ISSN

0018-9383

Type

jour

DOI

10.1109/16.75175

Filename

75175