Boron carbide(B4C)coatings have high reflectivity and are widely used as mirrors for free-electron lasers in the x-ray range.However,B4C coatings fabricated by direct-current magnetron sputtering show a strong compres...Boron carbide(B4C)coatings have high reflectivity and are widely used as mirrors for free-electron lasers in the x-ray range.However,B4C coatings fabricated by direct-current magnetron sputtering show a strong compressive stress of about-3 GPa.By changing the argon gas pressure and nitrogen-argon gas mixing ratio,we are able to reduce the intrinsic stress to less than-1 GPa for a 50-nm-thick B4C coating.It is found that the stress in a coating deposited at 10 m Torr is-0.69 GPa,the rms roughness of the coating surface is 0.53 nm,and the coating reflectivity is 88%,which is lower than those of coatings produced at lower working pressures.When the working gas contains 8%nitrogen and 92%argon,the B4 C coating shows not only-1.19 GPa stress but also a low rms roughness of 0.16 nm,and the measured reflectivity is 93%at the wavelength of 0.154 nm.展开更多
同步辐射广泛使用Au薄膜作为反射镜膜层,降低Au薄膜的粗糙度以减小散射信号仍是难点。基于国内外对Au薄膜的研究,本文采用在Au薄膜中插入Pt间隔层的方法,制备了新型Au-Pt薄膜。原子力显微镜(Atomic Force Microscope,AFM)测试结果表明:...同步辐射广泛使用Au薄膜作为反射镜膜层,降低Au薄膜的粗糙度以减小散射信号仍是难点。基于国内外对Au薄膜的研究,本文采用在Au薄膜中插入Pt间隔层的方法,制备了新型Au-Pt薄膜。原子力显微镜(Atomic Force Microscope,AFM)测试结果表明:采用1 nm厚的Au膜层和1 nm厚的Pt间隔层交替制备的方法所获得的新型Au-Pt薄膜,粗糙度小于0.3 nm,明显小于传统Au薄膜的粗糙度;通过X射线衍射(X-ray Diffractometer,XRD)测试可以发现,Pt间隔层的插入能够有效抑制Au膜结晶。随着Pt间隔层插入间隔的减小,Au膜结晶程度显著降低。根据AFM测试结果,使用IMD软件计算了传统Au薄膜以及新型Au-Pt薄膜的反射率,发现新型Au-Pt薄膜反射率比传统Au薄膜略有提高,同时新型Au-Pt薄膜的表面粗糙度更小,降低了散射强度,提升了反射镜的实际性能。本文为用于同步辐射的高传输效率、高反射率的Au-Pt薄膜反射镜的制备提供了参考。展开更多
基金Supported by the National Key R&D Program of China under Grant No 2016YFA0401304the National Natural Science Foundation of China under Grant Nos 61621001,U1732268 and 11875203the Shanghai Municipal Science and Technology Major Project under Grant No 2017SHZDZX02
文摘Boron carbide(B4C)coatings have high reflectivity and are widely used as mirrors for free-electron lasers in the x-ray range.However,B4C coatings fabricated by direct-current magnetron sputtering show a strong compressive stress of about-3 GPa.By changing the argon gas pressure and nitrogen-argon gas mixing ratio,we are able to reduce the intrinsic stress to less than-1 GPa for a 50-nm-thick B4C coating.It is found that the stress in a coating deposited at 10 m Torr is-0.69 GPa,the rms roughness of the coating surface is 0.53 nm,and the coating reflectivity is 88%,which is lower than those of coatings produced at lower working pressures.When the working gas contains 8%nitrogen and 92%argon,the B4 C coating shows not only-1.19 GPa stress but also a low rms roughness of 0.16 nm,and the measured reflectivity is 93%at the wavelength of 0.154 nm.
