Title :
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
fDate :
3/1/1991 12:00:00 AM
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;
Journal_Title :
Electron Devices, IEEE Transactions on
