温度对4H-SiC拉曼散射模的影响  

Temperature-dependent characteristics of Raman scttering modes in 4H-SiC

作　　者：苗瑞霞[1] 

机构地区：[1]西安邮电大学电子工程学院,陕西西安710121

出　　处：《科技创新导报》2013年第26期55-56,共2页Science and Technology Innovation Herald

基　　金：国家自然科学基金(No.51302215);陕西省教育厅科研基金(No.11JK0916)~~

摘　　要：在极端环境中应用的SiC器件,稳定性会受到温度的严重影响,其主要原因与材料晶格动力学因素随温度的变化有关。为了研究SiC单晶材料晶格动力学对温度的依赖关系,该文利用拉曼散射技术对材料4H-SiC材料进行了从30-300K温度范围的光谱测量。结果表明,拉曼光谱的声学模和光学模峰位均出现红移现象,但前者红移量较大。分析认为:声学模峰位红移的原因主要是由于晶格振动恢复力随温度升高而减小,使振动频率降低所致;而光学模峰位红移则是由于原子相对运动随着温度升高而加剧,减弱了原子和晶胞之间的相互作用,因而引起振动频率的降低。声学模较光学模峰位红移量小的主要原因是由于声学模对应的原子质量相对较大,由于温度对质量较大的影响程度要比质量较轻的低,因此声学模的红移量较光学模的小。The stability of SiC devices in extreme environments will be severely affected by the temperature. In this paper, Raman scattering techniques for 4H--SiC single crystal material is performed at the temperatures ranging from 30 to 300K. The results showed that the acoustic mode and optical mode peaks appear both redshift, but the former is a large amount of redshift. It is analyzed that the lattice vibrations restoring force decreases with increasing temperature, and the relative motion of atoms as the temperature elevated aggravated, which weakened the interaction between the atom and the cell, then the vibration frequency decreased. The redshift value of acoustic mode is lagrer than optical mode is due to the acoustic mode corresponding to the atomic mass is relatively large.

关 键 词：4H—SiC 拉曼模 声学模 光学模 

分 类 号：O474[理学—半导体物理]