This thesis describes the development of a method for characterization of multicrystalline silicon wafers based on hyperspectral imaging. The aim has been to show the distribution of radiative defects in silicon wafers. Commonly used methods are often time consuming and destructive or based on indirect measurements. Hyperspectral imaging is a fast, non-destructive method which measures the distribution of radiative defects directly.
The exact mechanisms of the radiative defects are still not fully understood, but by using hyperspectral imaging in addition to complementary measurements, new knowledge of their origins can be obtained.
One issue in this thesis has been to show the possibilities of using hyperspectral imaging to visualize radiative defects. In combination with multivariate curve resolution we can quickly extract the weak signals from the raw hyperspectral images.
A research facility for cooled hyperspectral photoluminescence imaging, has in parallel with the experiments, been developed and tested. The laboratory consists of two hyperspectral cameras, excitation source and two cryogenic coolers.
50 wafers from a silicon block have been studied using the hyperspectral imaging setup. Additionally, RGB images, conventional photoluminescence images and interstitial iron mapping have been acquired. The different datasets have been preprocessed and corresponding points were located in all image types before an affine transform was performed to align them to a common coordinate system. Selected spectral defects were used to make 3D visualization to show the distribution of defects through the silicon block
