Electron effective mass in ultrathin oxide silicon MOSFET inversion layers

Dragosavac, M., Paul, D.J. , Pepper, M., Fowler, A.B. and Buchanan, D.A. (2005) Electron effective mass in ultrathin oxide silicon MOSFET inversion layers. Semiconductor Science and Technology, 20(8), pp. 664-667. (doi: 10.1088/0268-1242/20/8/002)

Abstract

The effective mass (m*) of two-dimensional electrons in silicon metal–oxide–semiconductor field-effect transistors (MOSFETs), obtained from measurements of the thermal damping of Shubnikov–de Haas oscillations, has been studied as a function of electron density (ns) for samples with physical gate oxide thicknesses (dox) of 4.7 nm and 3.1 nm. For the latter at a low electron density, the ratio (aBrs)/dox (where rs is the interaction parameter and aB is the Bohr radius in the semiconductor) exceeded 2 and the modification of the electron–electron interaction potential by the presence of the metallic gate was expected to be manifested as a change in the interaction-driven enhancement of the effective mass with increasing rs. The deduced mass enhancement in both thin-oxide samples is well described by m*/mb = 0.96 + γrs, where mb is the bare band mass within the plane of confinement, and γ is a constant. Although the results from both samples are in good quantitative agreement with previous experiments on thicker-oxide MOSFETs, a small but significant difference in the extracted value of γ between the thin-oxide samples was observed. This difference cannot, however, be unambiguously interpreted as a true renormalization of m* caused by the screening effect of the gate.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Paul, Professor Douglas
• Authors: Dragosavac, M., Paul, D.J., Pepper, M., Fowler, A.B., and Buchanan, D.A.
• College/School: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• Research Group: Semiconductor Devices
• Journal Name: Semiconductor Science and Technology
• Publisher: IOP Publishing
• ISSN: 0268-1242
• ISSN (Online): 1361-6641