Possibilities and limitations of imaging spectroscopic reflectometry in optical characterization of thin films
| Authors | |
|---|---|
| Year of publication | 2015 |
| Type | Article in Proceedings |
| Conference | Conference on Optical Systems Design - Optical Fabrication, Testing, and Metrology V |
| MU Faculty or unit | |
| Citation | |
| Doi | http://dx.doi.org/10.1117/12.2191052 |
| Field | Solid matter physics and magnetism |
| Keywords | Imaging spectroscopic reflectometry; non-uniform thin films; optical parameters |
| Description | It is possible to encounter thin films exhibiting various defects in practice. One of these defects is area non-uniformity in optical parameters (e.g. in thickness). Therefore it is necessary to have methods for an optical characterization of non-uniform thin films. Imaging spectroscopic reflectometry provides methods enabling us to perform an efficient optical characterization of such films. It gives a possibility to determine spectral dependencies of a local reflectance at normal incidence of light belonging to small areas (37 mu m x 37 mu m in our case) on these non-uniform films. The local reflectance is measured by individual pixels of a CCD camera serving as a detector of an imaging spectroscopic reflectometer. It is mostly possible to express the local reflectance using formulas corresponding to a uniform thin film. It allows a relatively simple treatment of the experimental data obtained by imaging spectroscopic reflectometry. There are three methods for treating these experimental data in the special case of thickness non-uniformity, i.e. in the case of the same optical constants within a certain area of the film - single pixel imaging spectroscopic reflectometry method, combination of single-pixel imaging spectroscopic reflectometry method and conventional methods (conventional single spot spectroscopic ellipsometry and spectrophotometry), and multi-pixel imaging spectroscopic reflectometry method. These methods are discussed and examples of the optical characterization of thin films non-uniform in thickness corresponding to these methods are presented in this contribution. |
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