衬底温度对宽带隙立方氮化硼薄膜制备的影响

用射频溅射设备,采用两步法制备了宽带隙立方氮化硼(c-BN)薄膜.研究了在其他条件不变的情况下,成核阶段衬底温度对制备c-BN薄膜的影响.c-BN薄膜沉积在p型Si(100)衬底上,薄膜成分由傅里叶变换红外吸收谱标识.研究发现:衬底温度是立方BN薄膜成核的一个重要参数;要得到一定立方相体积分数的薄膜,成核阶段衬底温度有一个阈值,成核阶段衬底温度低于400℃,薄膜中没有立方相的存在;衬底温度为400℃时,薄膜中开始形成立方相;衬底温度达到500℃时,得到了立方相体积分数接近100%的薄膜,并且薄膜中立方相体积分数随着成核阶段衬底温度的升高而增加.还研究了成核阶段衬底温度对薄膜立方相红外吸收峰峰位的影响.结果显示:随着成核阶段衬底温度的升高,薄膜中立方相吸收峰峰位向低波数漂移,说明薄膜内的压应力随成核阶段衬底温度的升高而降低,薄膜中最小压应力为3.1GPa.

Influence of Substrate Temperature on Preparation of c-BN Thin Films with Wide Energy Gap

With a two-stage method,cubic boron nitride (c-BN) thin films are deposited on p-Si (100) by radio frequency sputter.The thin films are characterized by Fourier transform infrared spectroscopy.With all other conditions being held constant,the influence of the substrate temperature on the nucleation of c-BN is investigated.When the substrate temperature is below 400℃,the cubic phase can not be formed.Once the substrate temperature is above 400℃,the cubic phase starts to form.When the substrate temperature reaches 500℃,there is only the cubic phase (100%) in the thin films.It is evident that the relative content of c-BN in the films increases with the increase of the substrate temperature in the nucleation stage.We also investigate the effect of the substrate temperature in the nucleation stage on the FTIR absorption peak position and compressive stress in the thin films.The results show that different substrate temperatures in the nucleation stage result in different compressive stress in the thin films and that the compressive stress in the thin films decreases with the increase of the substrate temperature in the nucleation stage.The mechanism of c-BN nucleation is also discussed.