Defect-related luminescence and carrier transport in Ge-implanted SiO₂ layers on n-Si and p-Si

Ge ions of 100 keV were implanted into a 120 nm-thick SiO₂ layer on n-Si at room temperature, 300, and 500 °C while those of 80 keV were implanted into a SiO₂ layer on p-Si. Samples were subsequently annealed at 500 °C for 2 hours to obtain radiative defects from the implantation-induced non-radiative defects in the SiO₂. The maximum intensities of sharp violet photoluminescence from the SiO₂/n-Si and the SiC₂/p-Si samples were observed for samples implanted with doses of 1 × 10¹⁶ cm^-2 and 5 × 10¹⁵ cm^-2, respectively. Besides the violet, a broad orange luminescence was seen in the hot-implanted samples. According to the current-voltage (I-V) characteristics, the samples with radiative defects exhibited leakage currents and electroluminescence only in the negative-bias region, regardless of the type of substrate.