生长温度对6H-SiC上SiCGe薄膜发光特性的影响  

Influence of Growth Temperature on Photoluminescence of Thin SiCGe Films on 6H-SiC

作　　者：李连碧[1] 陈治明[1] 

机构地区：[1]西安理工大学电子工程系,陕西西安710048

出　　处：《发光学报》2010年第3期373-377,共5页Chinese Journal of Luminescence

基　　金：国家自然科学基金(60576044);西安理工大学优秀博士学位论文研究基金(602-210809)资助项目

摘　　要：利用低压化学气相淀积工艺在6H-SiC衬底成功制备了SiCGe薄膜。通过光致发光(PL)谱研究了生长温度对SiCGe薄膜发光特性的影响。结果表明:生长温度为980,1030,1060℃的SiCGe薄膜的室温光致发光峰分别位于2.13,2.18,2.31eV处;通过组分分析和带隙计算,认定该发光峰来自于带间辐射复合,证实了改变生长温度对SiCGe薄膜带隙的调节作用。同时,对SiCGe薄膜进行了变温PL测试,发现当测试温度高于200K时,发光峰呈现出蓝移现象。认为这是不同机制参与发光所造成的。SiC is an ideal material for manufacturing devices for use in power electronics,high temperature electronics and microwave communication.However,due to its wide band gap,SiC is not sensitive to longwavelength light ranging from most of the visible to the infrared region of the optical spectrum.This essentially limits its application for detection of visible and infrared light.A promising way to solve this problem is to adopt an SiCGe/SiC heterojunction structure,in which the ternary alloy SiCGe with appropriate composition is used as a light-absorption layer.In this paper,the ternary alloy SiCGe thin films were grown on 6H-SiC substrates in a conventional hot-wall CVD system.The influence of growth temperature on the photoluminescence（PL） and the structure of thin SiCGe films was investigated by PL spectroscopy and scanning electron microscope.The relation between the PL characteristics and structure of thin SiCGe films is discussed.The PL spectra of the thin SiCGe films grown at different growth temperatures（980,1 030 and 1 060 ℃） exhibit emis-sion peaks located at 2.13,2.18,2.31 eV,respectively.The component analysis and band-gap calculation of thin SiCGe films showed the PL peak comes from the radiative recombination between energy bands.And the regulatory effect of changing growth temperature on band gap of the thin SiCGe films is confirmed.The temperature-dependent PL spectra showed that the peak has an obvious blue-shift when the testing temperature increases higher than 200 K.It is due to different luminescent mechanisms.When the testing temperature is under 200 K,photoluminescence is related to the impurity and defect energy levels;as the testing temperature is higher,the radiative recombination is dominant in the luminescent mechanisms.

关 键 词：SiCGe薄膜 低压化学气相沉积 生长温度 光致发光 

分 类 号：O484.1[理学—固体物理] O482.31[理学—物理]