Instability in flatband voltage of SiO2 embedded with silicon nanocrystals

In this work, the flatband voltage shift of SiO2 embedded with silicon nanocrystal (nc-Si) annealed at different annealing temperature, different annealing time and under different temperature ramping rates are being investigated. The Si-ions are implanted into the SiO2 with very low energy. The instability of the flatband voltage shift is due to fact that there are remaining Si ions in the SiO2. It is observed that the flatband voltage shift can be reduced to a minimum of -0.1 V when the sample is annealed at 900 C for 20 mins using the conventional furnace annealing process. In contrast, rapid thermal annealing at 900 C for 100 s is not possible to eliminate the remaining Si ions. The number of remaining Si ions is found to be ~ 0.2 % of the total implanted doses.