中国物理B ›› 2013, Vol. 22 ›› Issue (9): 98502-098502.doi: 10.1088/1674-1056/22/9/098502

• INTERDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY • 上一篇    下一篇

Tight-binding study of quantum transport in nanoscale GaAs Schottky MOSFET

Zahra Ahangaria, Morteza Fathipourb   

  1. a Department of Electrical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran;
    b School of Electrical and Computer Engineering, University of Tehran, Tehran, Iran
  • 收稿日期:2013-01-04 修回日期:2013-04-20 出版日期:2013-07-26 发布日期:2013-07-26

Tight-binding study of quantum transport in nanoscale GaAs Schottky MOSFET

Zahra Ahangaria, Morteza Fathipourb   

  1. a Department of Electrical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran;
    b School of Electrical and Computer Engineering, University of Tehran, Tehran, Iran
  • Received:2013-01-04 Revised:2013-04-20 Online:2013-07-26 Published:2013-07-26
  • Contact: Zahra Ahangari E-mail:z.ahangari@iausr.ac.ir

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摘要： This paper explores the band structure effect to elucidate the feasibility of an ultra-scaled GaAs Schottky MOSFET (SBFET) in a nanoscale regime. We have employed a 20-band sp3d5s* tight-binding (TB) approach to compute E-K dispersion. The considerable difference between the extracted effective masses from the TB approach and bulk values implies that quantum confinement affects the device performance. Beside high injection velocity, the ultra-scaled GaAs SBFET suffers from a low conduction band DOS in the Γ valley that results in serious degradation of the gate capacitance. Quantum confinement also results in an increment of the effective Schottky barrier height (SBH). Enhanced Schottky barriers form a double barrier potential well along the channel that leads to resonant tunneling and alters the normal operation of the SBFET. Major factors that may lead to resonant tunneling are investigated. Resonant tunneling occurs at low temperatures and low drain voltages, and gradually diminishes as the channel thickness and the gate length scale down. Accordingly, the GaAs (100) SBFET has poor ballistic performance in nanoscale regime.

关键词: band structure, quantum confinement effects, resonant tunneling, Schottky MOSFET

Abstract: This paper explores the band structure effect to elucidate the feasibility of an ultra-scaled GaAs Schottky MOSFET (SBFET) in a nanoscale regime. We have employed a 20-band sp3d5s* tight-binding (TB) approach to compute E-K dispersion. The considerable difference between the extracted effective masses from the TB approach and bulk values implies that quantum confinement affects the device performance. Beside high injection velocity, the ultra-scaled GaAs SBFET suffers from a low conduction band DOS in the Γ valley that results in serious degradation of the gate capacitance. Quantum confinement also results in an increment of the effective Schottky barrier height (SBH). Enhanced Schottky barriers form a double barrier potential well along the channel that leads to resonant tunneling and alters the normal operation of the SBFET. Major factors that may lead to resonant tunneling are investigated. Resonant tunneling occurs at low temperatures and low drain voltages, and gradually diminishes as the channel thickness and the gate length scale down. Accordingly, the GaAs (100) SBFET has poor ballistic performance in nanoscale regime.

Key words: band structure, quantum confinement effects, resonant tunneling, Schottky MOSFET

中图分类号:  (Field effect devices)

  • 85.30.Tv
73.30.+y (Surface double layers, Schottky barriers, and work functions) 73.61.Ey (III-V semiconductors) 31.15.aq (Strongly correlated electron systems: generalized tight-binding method)