The thermal stability of atomic H plasma produced interface defects on Si-SiO2 stack

The Si-SiO₂ interface is still very important in crystalline silicon solar cell devices. While hydrogen is important for the passivation of defects at the Si-SiO₂ interface, atomic H at low temperatures can also introduce additional interface defects, which lead to substantially increased recombination. Previous work has shown that the defects are thermally unstable, however detailed properties of the defects have not been investigated. This paper investigates the thermal annealing behavior of Si-SiO₂ interface defects introduced by atomic hydrogen using carrier lifetime and capacitance-voltage measurements. We show that the annealing process of the defect is not characterized by a single activation energy but rather by a spread of activation energies. Capacitance-voltage results indicate that atomic H introduces defects fairly uniformly over the entire energy gap. Comparison of the annealing of corona-induced defects and defects introduced directly by atomic H reveals similar but not identical behavior, suggesting some differences in the nature of the defects introduced.