以Al(CH3)3和H2O为反应源,在270℃下用原子层淀积(ALD)技术在Si衬底上生长了Al2O3薄膜.采用X射线衍射(XRD)、X射线光电子能谱(XPS)、原子力显微镜(AFM)和傅立叶变换红外光谱(FTIR)等分析手段对Al2O3薄膜的热稳定性进行了研究.结果表明刚淀积的薄膜中含有少量A-OH基团,高温退火后,Al-OH基团几乎消失,这归因于Al-OH基团之间发生反应而脱水.退火后的薄膜中O和Al元素的相对比例(1.52)比退火前的(1.57)更接近化学计量比的Al2O3.FTIR分析表明,在刚淀积的Al2O3中有少量的-CH3存在,CH3含量会随热处理温度的升高而减少.此外,在高温快速热退火后,Al2O3薄膜的表面平均粗糙度(RMS)明显改善,900℃热退火后其RMS达到1.15nm.
Al2O3 thin films were grown by atomic layer deposition using trimthylaluminum (TMA) and water (H2O) as precursors at 270℃. Thermal stability of the Al2O3 film was explored by using X-ray diffraction, X-ray photoemission spectroscopy, Fourier transform infrared spectroscopy and atomic force microscopy. The results indicated that a small quantity of Al2O3 groups existed in the as-deposited samples, and almost disappeared after rapid thermal annealing (RTA) at 600℃ or higher. The O/Al ratio in the as deposited film was 1.57. And the ratio decreased to 1.52 in the RTA treated film, as expected in the case of stoichiometric Al2O3 FTIR spectroscopic revealed that there were also the presence of-CH3 species in the as-deposited films. The amount of-CH3 species decreased as annealing temperature increasing. In addition, after high temperatures RTA, the surface roughness of the Al2O3 films improved obviously, its RMS approached 1.15nm after 900℃ RTA.