基片温度对射频磁控溅射碲化铋薄膜微结构和表面形貌的影响

碲化铋材料是目前已知的室温下性能优异的热电材料之一。本文利用射频磁控溅射在不同基片温度下制备了碲化铋薄膜。研究发现,基片温度对薄膜的微结构和表面形貌影响显著。随着温度的提高,薄膜内晶粒尺寸都不同程度地增加。基片温度100℃以上碲化铋薄膜为Bi2Te3相为主的多晶结构,并具有良好的c轴择优取向,形成了六角层状结构。基片温度250℃时薄膜转变为BiTe相,并在表面生成Te长条状颗粒。应力分析表明碲化铋薄膜与Si(100)基片之间的残余应力受温度影响明显。

Influence of Substrate Temperature on Growth of RF Sputtered Bismuth Telluride Films

The bismuth telluride films were deposited by RF magnetron sputtering on substrate of Si(100) wafer,2 inch in diameter.The impacts of the growth conditions,such as the substrate temperature,sputtering power,and pressure,on the microstructures,surface morphologies,and interface properties of the bismuth telluride films were evaluated.The films were characterized with X-ray diffraction,and scanning electron microscopy.The results show that the substrate temperature strongly affects the microstructures and phase structure of the films.Depending on an increase of the substrate temperature,the grains grew to a varying degree.At 100℃,hexagonal Bi2Te3 phase dominated with c-axis as the preferred growth orientation.At 250℃,the Bi2Te3 phase changed into BiTe phase with formation of strip-like grains on the surface.In addition,the substrate temperature markedly influences the interfacial stress distribution.