Title :
Mechanically strained strained-Si NMOSFETs
Author :
Maikap, S. ; Yu, C.-Y. ; Jan, S.-R. ; Lee, Moon Ho ; Liu, C.W.
Author_Institution :
Dept. of Electr. Eng., Nat. Taiwan Univ., Taipei, Taiwan
Abstract :
The drain-current enhancement of the mechanically strained strained-Si NMOSFET device is investigated for the first time. The improvements of the drain current are found to be /spl sim/3.4% and /spl sim/6.5% for the strained-Si and control Si devices, respectively, with the channel length of 25 μm at the external biaxial tensile strain of 0.037%, while the drain-current enhancements are /spl sim/2.0% and /spl sim/4.5% for strained-Si and control Si devices, respectively, with the channel length of 0.6 μm. Beside the strain caused by lattice mismatch, the mechanical strain can further enhance the current drive of the strained-Si NMOSFET. The strain distribution due to the mechanical stress has different effect on the current enhancement depending on the strain magnitude and channel direction. The smaller current enhancement for strained-Si device as compared to the control device can be explained by the saturation of mobility enhancement at large strain.
Keywords :
MOSFET; leakage currents; mechanical strength; silicon compounds; stress-strain relations; Si; channel direction; channel length; control device; current drive; current enhancement; drain-current enhancement; external biaxial tensile strain; lattice mismatch; mechanical strain; mechanical stress; mechanically strained strained-silicon NMOSFETs; mobility saturation; strain distribution; strain magnitude; Capacitive sensors; Circuits; Electron mobility; Germanium silicon alloys; MOSFETs; Silicon germanium; Strain control; Stress; Substrates; Tensile strain;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2003.821671
