### Abstract

We report on the observation of enhanced high field hole velocity in strained Si/Si_{1-x}Ge_{x}/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/Si_{1-x}Ge_{x}/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/Si_{1-x}Ge_{x}/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, g_{msat}, 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 g_{msat} increase for high-speed, low-power VLSI applications is discussed.

Original language | English |
---|---|

Pages (from-to) | 1965-1971 |

Number of pages | 7 |

Journal | IEEE Transactions on Electron Devices |

Volume | 43 |

Issue number | 11 |

DOIs | |

Publication status | Published - Nov 1996 |

### Fingerprint

### ASJC Scopus subject areas

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

### Cite this

*IEEE Transactions on Electron Devices*,

*43*(11), 1965-1971. https://doi.org/10.1109/16.543034

**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.

Research output: Contribution to journal › Article

*IEEE Transactions on Electron Devices*, vol. 43, no. 11, pp. 1965-1971. https://doi.org/10.1109/16.543034

}

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, Leonard C

PY - 1996/11

Y1 - 1996/11

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

UR - http://www.scopus.com/inward/citedby.url?scp=0030287491&partnerID=8YFLogxK

U2 - 10.1109/16.543034

DO - 10.1109/16.543034

M3 - Article

VL - 43

SP - 1965

EP - 1971

JO - IEEE Transactions on Electron Devices

JF - IEEE Transactions on Electron Devices

SN - 0018-9383

IS - 11

ER -