Eur. Phys. J. B 66, 171-174 (2008)
https://doi.org/10.1140/epjb/e2008-00400-x

Chemical states of GeTe thin-film during structural phase-change by annealing in ultra-high vacuum

¹ Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang, 790-784, Republic of Korea
² Department of Physics, University of Seoul, Seoul, 130-743, Republic of Korea
³ AE Center, Samsung Advanced Institute of Technology, Yongin, 446-712, Republic of Korea
⁴ ATD Team, Semiconductor R&D Center, Samsung Electronics Co. Ltd., Yongin, 446-711, Republic of Korea

Corresponding author: ^a jmc@postech.ac.kr

Received: 20 November 2007
Revised: 17 June 2008
Published online: 30 October 2008

Abstract

The chemical states of GeTe thin film are investigated using high-resolution X-ray photoelectron spectroscopy (HRXPS) with synchrotron radiation, during amorphous to crystalline structural phase transition. As the temperature increases from 250 to 400 °C, we observe the rock-salt crystalline structure and phase with X-ray diffraction (XRD) and transmission electron microscopy (TEM). Spin-orbit splitting of the Ge 3d core-level spectrum clearly appears after annealing at 400 °C for 5 min. However, the binding energy of the Ge 3d_5/2 core-level peak of 29.8 eV does not change in the amorphous to crystalline structural phase transition. In the case of the Te 4d core-level, change in binding energy and peak shapes is also negligible. We assume that the Te atom is fixed at a site between the amorphous and crystalline phases. Although the structural environment of the Ge atoms changes during the structural phase transition, the chemical environment does not.