沉积温度对ALD制备HfO_(2)薄膜结构和性能的影响

Effects of Deposition Temperature on Structures and Properties of HfO_(2) Thin Films Prepared by ALD

采用原子层沉积(ALD)技术,以四(乙基甲基胺基)铪(TEMAHf)和去离子水为前驱体,沉积温度分别为150、200、250和300℃时,在单面抛光硅片和石英玻璃衬底上制备了HfO_(2)薄膜,并对薄膜进行了表征,研究了沉积温度对HfO_(2)薄膜结构和力学、光学及电学性能的影响。结果表明,当沉积温度低于200℃时,制备的HfO_(2)薄膜为非晶态,在300℃时制备的薄膜结晶度最高;随沉积温度的升高HfO_(2)薄膜厚度减小,表面粗糙度呈现先递增后下降的趋势,硬度和弹性模量均有所下降,残余应力不断增加,折射率略有增加,击穿电压先不变后减小,击穿场强先缓慢增大后明显减小,介电常数先增大后减小。沉积温度为300℃时制备的HfO_(2)薄膜的均匀性和致密性最好,沉积温度为200℃时制备的HfO_(2)薄膜的电学性能最佳。

By using atomic layer deposition(ALD) technology,with the tetra(ethylmethylamino) hafnium(TEMAHf)and deionized water as precursors,HfO_(2) thin films were prepared on the single-sided polished silicon wafer and the quartz glass substrate at the deposition temperatures of 150,200,250 and 300 ℃,respectively.The HfO_(2) thin films were characterized,and the effects of the deposition temperature on the structure,and mechanical,optical and electrical properties of HfO_(2) thin films were studied.The results show that when the deposition temperature is lower than 200 ℃,the prepared HfO_(2) thin film is amorphous,and the crystallinity of the HfO_(2)thin film prepared at 300 ℃ is the highest.With the increase of the deposition temperature,the thickness of the HfO_(2) thin film decreases,the surface roughness increases first and then decreases,the hardness and elastic modulus decrease,the residual stress continues to increase,the refractive index increases slightly,the breakdown voltage remains unchanged first and then decreases,the breakdown field strength increases slowly first and then decreases significantly,and the dielectric constant increases first and then decreases.The uniformity and density of the HfO_(2) thin film prepared at the deposition temperature of 300 ℃ are the best,and its electrical properties are the best at the deposition temperature of 200 ℃.