石榴石外延膜色散关系的确定和膜厚的测量

本文提出了确定石榴石外延膜的色散关系和测量膜厚的一种方法。充分利用分光光度计获得的透射光谱,在波长大于2μm,因而膜和衬底的吸收及色散近于可忽略时,由透过率的极值计算得到相应波长下膜的折射率。按干涉条件计算并推定出所有干涉极值的干涉级数,进而算出各干涉极值波长下膜的折射率。最后用最小二乘法求得科希色散公式的系数,从而得到该膜的色散关系。利用此色散关系就可计算膜厚。 关键词：

DETERMINATION OF THE DISPERSION AND THE MEASURE-MENT OF THE THICKNESS OF EPITAXIAL GARNET FILMS

A technique is proposed for determining the dispersion and measureing the thickness of epitaxial garnet films. Use is made fully of the transmission spectrum obtained by spe-ctrophotometer. When the wave length is greater than 2μm so that the absorption and dispersion become negligible, the refractive index at the corresponding wave length may be calculated from the extrema of the transmittance. According to the condition of in-terferrence, the order of interferrence is calculated and deduced for all interferrence extrema. The refractive indices of the film at the wave lengths corresponding to the interferrence extrema may be calculated. Finally the coefficience of Cauchy's dispersion formula are evaluated by the method of least squares, thus the dispersion relation is obtained for this film. Then, in making use of the dispersion relation, the thickness of the film may be calculated.