具有粗糙表面的氮化硅薄膜光热偏折谱分析

给出了一种分析表面粗糙度对氮化硅(SiNx)薄膜光热偏折谱(PDS)影响的简单方法.得出了光散射影响下,由PDS实验测得的薄膜的吸收系数与表面粗糙度的函数关系式.在此基础上,对PDS测得的具有纳米量级表面粗糙度的SiNx薄膜的吸收系数进行了修正,并进一步给出了不同薄膜厚度和表面粗糙度情况下,PDS测量结果的偏差.结果表明,在较低能量区域,PDS实验测得的薄膜吸收系数偏差较大,这种偏差不仅取决于薄膜的表面粗糙度,而且与薄膜的厚度相关,较大的表面粗糙度和较小的薄膜厚度将使其偏差显著增加;而在高能区域,这种偏差很小,可以忽略.

Analysis of Photothermal Deflection Spectroscopy of SiNx Thin Films with Rough Surface

A simple method is given to analyze the influence of the surface roughness on the photothermal deflection spectroscopy(PDS) of SiN-x thin films.The related formula between the optical absorbance coefficient measured by PDS(α-(PDS)) and surface rms roughness(σ) is obtained.Based on this result,α-(PDS) of the SiN-x thin film with the nano-sized σ is corrected and named α-(true).Furthermore,the influence of the different σ and film thickness(d-f) on α-(PDS) is discussed.The results indicate that the deviation between α-(PDS) and α-(true) is considerable on the side of low energy,which is not only dependent on σ but also related to d-f.The bigger σ and the smaller d-f will make the deviation increase obviously.But it can be neglected on the side of high energy.