Ge_2Sb_2Te_5薄膜相变行为及其对光存储特性影响  

Phase transition behavior of Ge_2Sb_2Te_5 films and its effect on optical properties

作　　者：张庆瑜[1] 都健[1] 潘石[2] 吴世法[2] 

机构地区：[1]大连理工大学三束材料改性国家重点实验室,辽宁大连116024 [2]大连理工大学物理系,辽宁大连116024

出　　处：《大连理工大学学报》2007年第6期781-785,共5页Journal of Dalian University of Technology

基　　金：科技部重大基础研究前期研究专项资助项目(2004CCA03700)

摘　　要：采用射频磁控溅射方法,在石英玻璃基片上制备了Ge2Sb2Te5相变薄膜.X射线衍射分析表明:室温沉积的薄膜为非晶态;170℃真空退火后,薄膜转变为晶粒尺度约为17nm的面心立方结构;250℃退火导致晶粒尺度约为40nm的密排六方相出现.研究了室温至450℃下薄膜相变的热力学性能.差热分析显示:薄膜的非晶相向fcc相转变的相变活化能为(2.03±0.15)eV;fcc相向hex相转变的相变活化能为(1.58±0.24)eV.薄膜反射率测量表明:面心相与非晶相的反射率对比度随着波长从400nm增加到1000nm在15%～30%变化,六方相与非晶相的反射率对比度在30%～40%.不同脉冲宽度的激光对非晶态薄膜的烧蚀结果显示:激光的能量密度对薄膜的记录效果有显著影响,在5mW、50ns的脉冲激光作用下,Ge2Sb2Te5薄膜具有最好的光存储效果.Using a radio-frequency reactive magnetron sputtering method, Ge2Sb2Te5 films were grown on quartz substrates at room temperature. X-ray diffraction analysis revealed the as-deposited films to be amorphous. The films have a face-center-cubic （fcc） structure with the grain size of 17 nm and hexagonal （hex） structure with the grain size of 40 nm after annealed at 170 ℃ and 250℃ in a vacuum chamber, respectively. The thermodynamics behavior of the phase transition of the films was studied at the temperature ranging from room temperature to 450℃. It is found that the activation energy of phase transition is （2.03 ± 0. 15） eV from amorphous to fcc phase and （1.58 ± 0.24） eV from fcc phase to hex phase by DSC. The reflection contrast increases from 15% to 30% for fcc films and from 30% to 40% for hex films with increasing the wavelength from 400 to 1 000 nm. The influence of pulse width on the phase transition shows that energy density of laser has effect on recording behavior of the film, and Ge2Sb2Tes films have the best optical properties under the irradiation of a 5 mW and 50 ns pulsed laser.

关 键 词：GE2SB2TE5薄膜 射频磁控溅射 相变 光学特性 激光辐照 

分 类 号：O469[理学—凝聚态物理]