Metal–semiconductor junctions on p-type strained Si1−xGex layers

Abstract

The electrical properties of Schottky junctions on high-quality p-type strained Si1−xGex layers have been studied for Ge fractions 0≤x≤0.24. A multicrystal high-resolution x-ray diffractometer was used to investigate the sample’s quality and the strain state and to accurately determine the Ge fraction in the fabricated devices. Several different metals, having a wide range of barrier heights, were used to reach conclusions on the variation of barrier height with the Ge content in the grown strained Si1−xGex layers. It has been found that the Schottky barrier height decreases with increasing Ge fraction in the Si1−xGex layer for the different metals investigated. The change in the barrier height with x has been found to be directly correlated to the valence band discontinuity in the Si/Si1−xGex heterojunction.