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This thesis examines carrier lifetime instabilities in oxygen-rich boron-doped p-type Czochralski-grown silicon (Cz-Si) with the focus on the permanent deactivation of the boron-oxygen (BO)-related defect center leading to a regeneration in lifetime. In order to resolve contradictory statements reported previously in the literature concerning the mechanism of regeneration in this thesis, passivated emitter and rear solar cells (PERCs) fabricated on boron-doped p-type Cz-Si wafers are regenerated in darkness by carrier injection via application of a forward-bias voltage V_appl at elevated temperatures. The regeneration kinetics is analyzed under regeneration conditions by measuring the total recombination current of the solar cell at the actual regeneration temperature at varying applied voltages Vappl. In parallel, we measure the electroluminescence signal emitted by the solar cell at different time steps during regeneration to directly determine the injected excess carrier concentration Delta{n} at each applied forward-bias voltage V_appl. The deactivation rate constant R_de of the BO defect is determined from the measured time-dependent cell current. The experimental results show unambiguously for the first time that R_de increases proportionally with Delta{n} during the regeneration process, solving the inconsistencies reported in the literature under actual regeneration conditions. To identify the impact of hydrogen on the BO-related lifetime degradation and regeneration kinetics, different amounts of hydrogen are introduced into the silicon bulk by rapid thermal annealing (RTA) treatment in an infrared conveyor-belt furnace quantified by measurements of the silicon resistivity increase. The silicon resistivity increases under dark-annealing due to hydrogen passivation of boron dopant atoms. The hydrogen source in our experiments are hydrogen-rich silicon nitride (SiN_x:H) layers deposited on the silicon wafer surfaces. Varying the peak-temperature of the RTA step indicates that there exists a ...