Theory and observation of enhanced, high field hole transport in Si1-xGex quantum well p-MOSFET's

Kaushik Bhaumik, Yosi Shacham-Diamand, J. P. Noel, Joze Bevk, Leonard C Feldman

Research output: Contribution to journalArticle

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Abstract

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.

Original languageEnglish
Pages (from-to)1965-1971
Number of pages7
JournalIEEE Transactions on Electron Devices
Volume43
Issue number11
DOIs
Publication statusPublished - Nov 1996

Fingerprint

Semiconductor quantum wells
field effect transistors
quantum wells
MOSFET devices
metal oxide semiconductors
junction transistors
Strain relaxation
Electron beam lithography
Transconductance
very large scale integration
transconductance
Molecular beam epitaxy
budgets
Heterojunctions
Transistors
molecular beam epitaxy
lithography
Gases
high speed
electron beams

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Physics and Astronomy (miscellaneous)

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Theory and observation of enhanced, high field hole transport in Si1-xGex quantum well p-MOSFET's. / Bhaumik, Kaushik; Shacham-Diamand, Yosi; Noel, J. P.; Bevk, Joze; Feldman, Leonard C.

In: IEEE Transactions on Electron Devices, Vol. 43, No. 11, 11.1996, p. 1965-1971.

Research output: Contribution to journalArticle

Bhaumik, Kaushik ; Shacham-Diamand, Yosi ; Noel, J. P. ; Bevk, Joze ; Feldman, Leonard C. / Theory and observation of enhanced, high field hole transport in Si1-xGex quantum well p-MOSFET's. In: IEEE Transactions on Electron Devices. 1996 ; Vol. 43, No. 11. pp. 1965-1971.
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