The impact of the post-implantation annealing conditions on the electrical characteristics of P-implanted homogeneous emitter silicon solar cells with aluminum-back surface field, 156 mm × 156 mm in size, is investigated. Based on a measurement of the internal quantum efficiency (IQE) and scanning capacitance microscopy observation, we discuss the behavior of the phosphorous prepared by annealing in a nitrogen atmosphere (PIA) and oxidation (PIO) after implantation of P and its impact on the cell characteristics. Implantation of P with step rotation was implemented while wafer made one rotation. A uniform thickness amorphous layer was formed in each side wall of the texture. The $\boldsymbol{p}$ - $\boldsymbol{n}$ junction depth of a P-implanted emitter with PIO is deeper than that of an emitter with PIA. Sheet resistance of P-implanted emitter with PIO shows higher value compared to that of PIA. The solar cell with PIO indicated a higher IQE at shorter wavelength. Solar cells with PIO show an improvement in the short-circuit current, open-circuit voltage, and conversion efficiency compared to cells subjected to PIA. A maximum conversion efficiency of 19.41% was obtained.