Gettering of Oxygen onto Buried Defect Layer in Hydrogen Implanted Silicon Wafers after Low Temperature Surface Saturation by Oxygen and Vacuum Annealing

摘要

The 10 Ω·cm boron-doped Cz-Si wafers were implanted by 100 keV H~+ and He~+ ions with doses (2.0/4.0)·10~(16) cm~(-2) and then subjected to low-temperature saturation by oxygen from DC plasma source and annealing in vacuum at 250 °C or 500 °C for 4 h. SIMS measurements have shown that oxygen plasma pre-treatment of H~+-implanted silicon wafers and their subsequent vacuum low-temperature annealing result in gettering of oxygen from the surface onto the buried defect layer. Measurements in the scanning electron beam induced voltage mode of SEM have exhibited the formation of inhomogeneously distributed contrast, induced by the presence of the buried electrically active extended defects at depths close to a maximal oxygen content. This contrast represents a system of dark spots with a more or less ordered structure the dimensions of that are dependent on the dose of H~+ pre-implantation.