溅射参数对Ge2Sb2Te5薄膜光学常数的影响

研究了溅射参数对Ge2Sb2Te5薄膜的光学常数随波长变化关系的影响，结果表明：(1)当溅射功率一定时，随溅射氩气气压的增加Ge2Sb2Te5薄膜的折射率先增大后减小，而消光系数先减小后增大.(2)当溅射氩气气压一定时，对于非晶态薄膜样品，在500nm波长以下，折射率随溅射功率的增加先增加后减小，消光系数则逐渐减小；在500nm以上，折射率随溅射功率的增加逐渐减少，消光系数先减小后增加.对于晶态薄膜样品，在整个波长范围折射率随溅射功率的增加先减小后增加，消光系数则逐渐减少.(3)薄膜样品的光学常数都随波长的变化而变化，在长波长范围变化较大，短波长范围变化较小.探讨了影响Ge2Sb2Te5薄膜光学常数的机理.

Effects of Sputtering Parameter on Optical Constants of Ge2Sb2Te5 Thin Films

The effects of sputtering parameter on the optical constants(n,k)of Ge2Sb2Te5 thin films in the wavelength range of 300—830nm were studied.The results show:(1)When the sputtering power is constant,the refractive index(n) first increases and then decreases with the increasing of Ar gas pressure,whereas the extinction coefficient(k) changes with Ar gas pressure in a contrary way to that of n.(2)When the sputtering Ar gas pressure is constant,for the amorphous thin films,in the wavelength range of 300—500nm,the refractive index first increases and then decreases with the increasing power,whereas the extinction coefficient decreases monotonically.In the wavelength range of 500—830nm,the refractive index decreases with the sputtering power,while the extinction coefficient first decreases and then increases.For the crystalline thin films,in the wavelength range of 300—830nm,the refractive index first decreases and then increases,whereas the extinction coefficient decreases.(3)The extent of the influence of sputtering parameter on n and k also changes with the wavelength,which is greater in the long wavelength region than that in the short wavelength region.The mechanism by which the optical constants of the Ge2Sb2Te5 thin films are affected by sputtering parameter has been discussed based on the variation of the density and microstructure of the films.