蒸镀法制备纳米晶Be薄膜及微观组织演化研究

Fabrication of Nanocrystalline Be Films by Evaporation Method and Investigation on Microstructure Evolution

采用蒸镀法在Si(001)基片上制备晶粒尺寸35 nm,RMS表面粗糙度优于11 nm的Be薄膜。蒸发温度由1 050℃升高至1 150℃时,Be薄膜表面形态由细小等轴晶(1 050～1 070℃)→纤维晶(1 080～1 110℃)→粗大等轴晶(1 120～1 130℃)→粗大纤维晶(1 150℃),其表面粗糙度先增加后略微下降。XRD分析结果表明:不同蒸发温度下沉积Be薄膜均主要由hcp结构的(αBe)相组成,其表面显露晶面随温度增加由(002)向(100)晶面转变。Be原子沉积速率随温度增加呈现指数函数关系增大。实验结果显示:采用水冷Si基片并控制原子沉积速率在2.3 nm/min,能够制备出单相(αBe)纳米晶薄膜。

A nanocrystalline Be films with a grain size of 35 nm and root mean square （RMS） roughness of 11 nm were fabricated by an evaporation method. As the temperature increases from 1 050℃ to 1 150℃, the mor- phology of Be film shows a transition form a small equiaxed grain （ 1 050 ~ 1 070℃ ）, a fibrous crystal （ 1 080 -1110℃）, a large equiaxed grain （1 120 - 1 130℃） to a large fibrous crystal （1 150℃）, and the RMS roughness enhances firstly and then decreases slightly. X - ray diffraction analysis indicates that the Be films at different deposition conditions consist of hcp structure a - Be phase, its primary crystal plane on the film sur- face changes from （002） to plane with the increase of evaporation temperature. The deposition velocity of Be atom enhances as an exponential function of evaporation temperature. It was found that, if we use Si substrate cooled by the circulation water and can accurately control the deposition velocity at 2.3 nm/min, the nanocrys- talline Be films with a single ct -Be phase can be fabricated.