Principal Component Analysis (PCA) of Surface Contamination by TOF-SIMS

Static time of flight secondary ions mass spectrometry (TOF-SIMS) is a qualitative analysis technique with a high detection limit capable of achieving parts per million (ppm) levels [1] and sub monolayer surface detection. Due to its high sensitivity, the data obtained may contains more than hundreds of peaks including information about sample composition, chemical compound, fragments ions, sample purity, and etc. [2]. Therefore, TOF-SIMS data interpretation is complicated and time consuming especially for unknown contamination. These challenges could be overcome by Principal Component Analysis (PCA). PCA is one of a multivariate method used to identify mass peak spectral in various principal component loadings when processing large data sets such as TOF-SIMS data. This paper presents a study of surface contamination analysis using image based PCA to find out the parent ion of the contaminant.