离子注入Si损伤分布的光谱法多层分析

应用多层模型和最优化方法,由实验测得的离子注入Si的椭偏光谱以及单晶Si和离子注入非晶Si的光学常数,能分析离子注入Si的损伤分布。我们测量了2.1—4.6eV能量范围的椭偏光谱和光学常数,建立了多层计算模型和最优化方法。在模拟分析的基础上,计算了能量为40keV,剂量分别为4×10¹³和1.4×10¹⁴cm^-2的As⁺注入Si的损伤分布,并与背散射测量的结果比较。用多层模型和最优化方法也能从光谱分析其它物理量的分布,只要这些物理量对光学性质有显著的影响,并且在测量过程中不随光子能量而改变。 关键词：

MULTILAYER ANALYSIS OF DAMAGE PROFILE IN ION IMPLANTED SILICON BY OPTICAL SPECTROMETRY

The damage profile of ion implanted silicon can be calculated from the spectroscopic elli-psometric data as well as the optical constants of crystalline and ion implanted amorphous state of silicon by means of optimization with a multilayer model. We measured the ellipsometric spectra and optical constants of ion implanted samples in the spectral range from 2.1 to 4.6 eV In the sense of optical characteristics, the degree of damage is defined using complex refractive index. We performed the calculation of damage profiles of 40 keV As⁺ implanted Si 〈111〉 at dosage of 4×10¹³ and 1.4×10¹⁴ ion cm^-2, respectively, on the basis of simulated tests. The depth profiles of damage were obtained and compared with the experimental results of He⁺ back-scattering. The method of multilayer analysis can also be used to determine the profiles of other parameters of interest from optical spectra as long as the parameters markedly influence the optical response and do not depend upon the photon energy.