Interface formation in Yb/Si(111) system has been investigated by AES and EELS spectroscopy and in situ Hall measurements at room temperature. It was established that interface formation process may be divided into five stages: 1) 2D growth of Yb (up to two monolayers), 2) intermixing and formation of 2D Yb silicide, 3) formation of 3D silicode islands, 4) growth of Yb on 3D silicide islands, 5) coalescence of 3D Yb-Yb silicide islands and formation of continuous Yb film. We attribute the observed conductivity character in Yb/Si(111) system to the evaluation of morphological and electrical properties of the growing Yb layer (2D Yb, silicide, metal) rather than to the changes within the space charge layer under the surface. Two-layer calculations have shown that holes are majority carriers in the deposited mobility and surface hole concentration within the coverage range below 6 ML where formation of a continuous Yb silicide film completes. Conductivity oscillations are explained by transition from semiconductor-type conductivity at the first growth stage (2D Yb growth) to metal-like conductivity of 2D and 3D Yb silicide films. It was shown that thin continuous Yb film (13 Ml) has the resistivity (16 μΩ-cm) close to the bulk refractory metals.

Date Published: 17 June 2003
PDF: 8 pages
Proc. SPIE 5129, Fundamental Problems of Optoelectronics and Microelectronics, (17 June 2003); doi: 10.1117/12.502399

Published in SPIE Proceedings Vol. 5129:
Fundamental Problems of Optoelectronics and Microelectronics
Yuri N. Kulchin; Oleg B. Vitrik, Editor(s)