Observation of strain relaxation in Si1-xGex layers by optical and electrical characterisation of a Schottky junction

2001-05-01
Turan, Raşit
Aslan, B
Nur, O
Yousif, MYA
Willander, M
We have studied the effect of the strain relaxation on the band-edge alignments in a Pt/p-Si1-xGex Schottky junction with x = 0.14 by internal photoemission spectroscopy and current-voltage measurements. We have shown that the variations in the band-edge alignments can be observed directly by measuring the optical and electrical properties of a simple Schottky junction. The strain in the Si1-xGex layer has been partially relaxed by thermal treatments at two different temperatures, The degree of relaxation and other structural changes have been determined by a high-resolution X-ray diffractometer. Both optical and electrical techniques have shown that the barrier height of the Pt/Si0.86Ge0.14 junction increases with the amount of relaxation in the Si1-xGex layer. This shows that the valence-band edge of the Si1-xGex layer moves away from the Fermi level of the Pt/Si1-xGex junction. The band-edge movement results from the increase in the band gap of the Si1-xGex layer after the strain relaxation. This result agrees with the theoretical predictions for the strain-induced effects on the Si1-xGex band structure.

Citation Formats
R. Turan, B. Aslan, O. Nur, M. Yousif, and M. Willander, “Observation of strain relaxation in Si1-xGex layers by optical and electrical characterisation of a Schottky junction,” APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING, vol. 72, no. 5, pp. 587–593, 2001, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/36211.