Functional passivation of high resistivity p-type c-Si wafer surfaces was achieved using 10 nm Al2O3 layers and low temperatures for both the thermal ALD process and post-deposition anneal. Effective lifetime values higher than 1 ms were measured at excess carrier density Δn=1015 cm-3. This result was reached in combination with temperatures of 100 °C and 200 °C for the Al2O3 layer deposition and anneal, respectively. The Al2O3/c-Si interface was characterized using conductance-voltage and capacitance-voltage measurements. In particular, significantly reduced interface density of the electrically active defects Dit ∼ 2 x 1010 eV-1cm-2 was detected, which enabled excellent chemical passivation. The measured density of fixed charges at the interface, Qf, after anneal were in the range +1 x 1012 to -1 x 1012 cm-2 indicating that both inversion and accumulation conditions result in relevant field-effect …