退火对栅介质SrHfON薄膜性能的影响

采用射频磁控溅射法在Si衬底上制备新型栅介质SrHfON薄膜。采用X射线衍射(XRD)仪、高分辨透射电镜(HRTEM)和X射线光电子谱(XPS)分析退火对SrHfON薄膜的界面形态、薄膜的结构和电学性能的影响。结果表明,SrHfON薄膜经900℃退火后仍保持非晶态,表现出良好的热稳定性。SrHfON薄膜与Si衬底的界面主要由HfSixOy和SiO2组成。以SrHfON薄膜为栅介质的MOS电容结构具有较小的漏电流密度,并且漏电流密度随着退火温度的升高而减小。在外加偏压(Vg)为+1V时样品在沉积态和900℃退火后的漏电流密度分别为4.3×10-6和1.2×10-7A/cm2。研究表明,SrHfON薄膜是一种很有希望替代SiO2的新型栅介质材料。

Effects of Annealing on the Properties of SrHfON Gate Dielectric Films

SrHfON thin films were prepared on p-type Si substrates by reactive radio-frequency sputtering deposition,The effects of annealing on the interface between SrHfON film and Si substrate,the structure and the electrical properties of the as-deposited and annealed films have been investigated systematically.The results of XRD and HRTEM show that the SrHfON films are amorphous even after annealing at 900 °C.The interface between SrHfON film and Si substrate is composed of HfSixOy and SiO2 confirmed by XPS.The measurements indicate that MOS capacitors using the SrHfON films as gate dielectrics have lower leakage current densities and the leakage current densities decrease with increasing of RTA temperatures.The leakage current densities at Vg=+1 V for the as-deposited and annealed films are 4.3×10-6 A/cm2 and 1.2×10-7 A/cm2,respectively.The analyses results show that SrHfON films will be a promising candidate for replacing SiO2 gate dielectric.