TY - JOUR
T1 - Theory and observation of enhanced, high field hole transport in Si1-xGex quantum well p-MOSFET's
AU - Bhaumik, Kaushik
AU - Shacham-Diamand, Yosi
AU - Noel, J. P.
AU - Bevk, Joze
AU - Feldman, L. C.
N1 - Funding Information:
Manuscript received April 24, 1995; revised March 20, 1996. The review of this paper was arranged by Editor G. W. Neudcck. This work was performed in part at the Cornell Nanofabrication Facility at Cornell University, supported by the National Science Foundation under Grant ECS-8619049, Cornell University, and industrial affiliates. K. Bhaumik is with McKinsey and Company, Houston TX 77010 USA. Y. Shacham-Diamond is with the School of Electrical Engineering and Cornell Nanofabrication Facility, Cornell University, Ithaca, NY 14853-540 1 USA. J.-P. Noel is with the Institute for Microstructural Sciences, National Research Council of Canada, Ottawa, Ont., Canada KIA 0R6. J. Bevk is with AT&T Bell Laboratories, Murray Hill, NJ 07974-2070 USA. L. C. Feldman is with the Department of Physics, Vanderbilt University, Nashville, TN 37203 USA Publisher Item Identifier S 001 8-9383(96)07733-7.
PY - 1996
Y1 - 1996
N2 - We report on the observation of enhanced high field hole velocity in strained Si/Si1-xGex/Si quantum wells. This effect manifests itself in the drive current capability of nanometer scale p-channel Quantum Well Metal-Oxide-Semiconductor-Field-Effect-Transistors (p-QWMOSFET's). The high-field transport of a two-dimensional hole gas confined in a Si/Si1-xGex/Si quantum well is formulated and solved. The results indicate an increase in the hole saturated drift velocity in strained SiGe quantum wells with increasing Ge mole fractions up to x = 0.5. This is a consequence of the optical phonon spectrum of the strained SiGe alloy remaining Si-like (i.e., high energy) while the carrier transverse effective mass decreases with higher Ge content. To investigate the theoretical prediction of increased high-field drift velocity, p-QWMOSFET's were fabricated with Si/Si1-xGex/Si quantum well heterostructures grown by Molecular Beam Epitaxy (MBE) with varying Ge mole fractions, x. The fabrication sequence maintained a low thermal budget to prevent strain relaxation in the SiGe layer and involved a mixed optical/electron beam lithography scheme to define junction-isolated transistors with a minimum drawn gate lengths of 200 nm. The measured saturated transconductance, gmsat, of the p-QWMOSFET's were 20-50% higher than that of a reference Si p-MOSFET under equivalent biasing conditions. The importance of this gmsat increase for high-speed, low-power VLSI applications is discussed.
AB - We report on the observation of enhanced high field hole velocity in strained Si/Si1-xGex/Si quantum wells. This effect manifests itself in the drive current capability of nanometer scale p-channel Quantum Well Metal-Oxide-Semiconductor-Field-Effect-Transistors (p-QWMOSFET's). The high-field transport of a two-dimensional hole gas confined in a Si/Si1-xGex/Si quantum well is formulated and solved. The results indicate an increase in the hole saturated drift velocity in strained SiGe quantum wells with increasing Ge mole fractions up to x = 0.5. This is a consequence of the optical phonon spectrum of the strained SiGe alloy remaining Si-like (i.e., high energy) while the carrier transverse effective mass decreases with higher Ge content. To investigate the theoretical prediction of increased high-field drift velocity, p-QWMOSFET's were fabricated with Si/Si1-xGex/Si quantum well heterostructures grown by Molecular Beam Epitaxy (MBE) with varying Ge mole fractions, x. The fabrication sequence maintained a low thermal budget to prevent strain relaxation in the SiGe layer and involved a mixed optical/electron beam lithography scheme to define junction-isolated transistors with a minimum drawn gate lengths of 200 nm. The measured saturated transconductance, gmsat, of the p-QWMOSFET's were 20-50% higher than that of a reference Si p-MOSFET under equivalent biasing conditions. The importance of this gmsat increase for high-speed, low-power VLSI applications is discussed.
UR - http://www.scopus.com/inward/record.url?scp=0030287491&partnerID=8YFLogxK
U2 - 10.1109/16.543034
DO - 10.1109/16.543034
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AN - SCOPUS:0030287491
SN - 0018-9383
VL - 43
SP - 1965
EP - 1971
JO - IEEE Transactions on Electron Devices
JF - IEEE Transactions on Electron Devices
IS - 11
ER -