Large enhancement of the Hall mobility of the majority carrier in p-type Czochralski silicon after porous silicon damage: solutions for gettering efficiency improvement
The gettering of Czochralski silicon with a sacrificial porous silicon layer (PSL) is shown to enhance external and chemical gettering efficiency. The study of the majority charge carrier mobility of holes proves the effectiveness of the repeating iterative gettering process under a SiCl4/N2 atmosphere in comparison with external conventional gettering techniques. For aluminium and phosphorous gettering with interfacial PSL, following the segregation thermodynamics theory, it is established that the superposition of the gettering effects has occurred. This can, indeed, be explained by the obtained results, which agreed well with the theoretical model of segregation. Furthermore, for iterative and repeating gettering under SiCl4, based on gettering efficiency, it is found that a two- and three-times process with a given gettering layer dg is more efficient than one run with 2dg and 3dg.