Heteroepitaxial sputtered Ge on Si (100): Nanostructure and interface morphology

¹  CoreCom - via G. Colombo, 81, 20133 Milano, Italy, EU
²  Research Institute for Technical Physics and Materials Science - Konkoly-Thege M. út 29-33, H-1121 Budapest, Hungary, EU
³  MDM National Laboratory CNR-INFM - via C. Olivetti, 2, 20041 Agrate Brianza (MI), Italy, EU
⁴  Politecnico di Milano, Department of Electronics and Information - via Ponzio, 34-5, 20133 Milano, Italy, EU
⁵  Politecnico di Milano, Department of Energy - via Ponzio, 34-3, 20133 Milano, Italy, EU

Corresponding author: pietralunga@elet.polimi.it

Received: 1 September 2009
Accepted: 6 October 2009

Abstract

Epitaxial growth of Ge thin films onto (100) silicon by DC-Pulsed Magnetron Sputtering was realized and proved by X-ray and electron diffraction. Transmission and high-resolution electron microscopy across the interface region directly confirmed a high degree of epitaxy and show that planar defects and threading dislocations are the relevant lattice imperfections. Electron microscopy shows that a post-deposition rapid thermal annealing process, up to 673 K, is effective to defect annihilation. The films grow single crystalline, slightly misoriented, below 0.1 degrees. A weak roughness around 0.6 nm, was measured both at the Ge-Si interface and at the film surface. The Ge films grown onto n-type Si show the rectifying electrical behaviour typical of p-type semiconductors.