Raman investigation of hydrogen-implanted and DC hydrogen-plasma-treated Cz Si wafers

Abstract

The general goal of this work is to demonstrate that the buried defect layer created by hydrogen implantation can serve as a gettering region for hydrogen introduced from a DC plasma and to study the efficiency of this gettering affected by the implantation regimes. Standard n-type 4.5 Ω⋅cm Cz Si wafers were implanted by hydrogen ions with an energy of 100 keV and different doses of 1 × 1014, 1 × 1015, or 5 × 1015 atoms/cm2 at temperatures of 150, 300, 400, or 500 °C. After implantation, hydrogen was introduced to the wafers from the DC plasma at 150 °C. For a comparative estimation of the hydrogen concentration in the wafers implanted in different regimes Raman spectroscopy was used. The peaks of the Raman spectra associated with molecular hydrogen (H2), vacancy-hydrogen (V–H), and silicon–hydrogen (Si–H) complexes were studied depending on the implantation conditions. It is demonstrated that peaks of Raman spectra depend significantly on the dose and temperature of implantation. This means that the concentration of hydrogen in the wafers could be determined from the concentration and type of defects formed by hydrogen implantation. Maximum peaks associated with H2, Si–H, and V–H complexes were observed for the samples implanted at a temperature of 500 °C.