衬底温度对脉冲激光沉积多晶锗薄膜的影响

Effect of Substrate Temperature on Deposition of Polycrystalline Germanium Thin Films by Pulsed Laser

以p型单晶硅为衬底基板,在不同衬底温度下,采用脉冲激光沉积法结合退火处理,制备了多晶锗薄膜。利用包括拉曼光谱仪和椭圆偏振仪等各种测试方法,对薄膜的形貌和微观结构进行了分析表征。结果表明,不同衬底温度下制备的锗薄膜的形貌结构有明显不同。当硅衬底的温度为300℃时,锗薄膜已经完全晶化,是结晶质量良好的多晶锗薄膜,拉曼峰谱位于297cm-1处,晶体取向为(111),(220),(311)。而衬底温度低于100℃时,获得的是非晶锗薄膜,只有经过450℃以上的退火处理后,才转化为多晶锗薄膜,拉曼光谱位于298.2cm-1处,半高宽9.5cm-1,是具有(111)择优取向的多晶锗膜。

Germanium films were prepared by pulsed laser deposition on silicon substrate at different temperatures and then post annealed.The morphology and crystalline structure of germanium films were investigated by normal methods including Raman spectroscopy and ellipsometer.The results show that the morphology and crystalline structure of the germanium films are different for different substrate temperatures.When the substrate temperature is 300℃,germanium film with high crystallinity is obtained,the crystal orientations are(111),(220)and(311),and the Raman peak is located at about 297 cm^-1.In addition,the annealing treatment can optimize the structure of the germanium film.When the germanium film deposited at 100℃is annealed at 450℃for 30 min,the Raman peak locates at 298.2 cm^-1,and the FWHM is 9.5 cm^-1,which prove that the annealing-treated film is a polycrystalline germanium film with(111)preferred orientation.