We characterized the effects of doping on static and dynamic charge across the depletion region in epitaxial Si:P+ / Si:B-substrate. The blanket characterizations show presence of substitutional doping in epitaxial Si:P films. This is seen in close relation between D-SIMS and HRXRD characterizations. Strain measurements show increased tensile strain with doping, indicating that higher concentration of P does go into substitutional positions. We further performed electron holography measurements to characterize the field in depletion region. The mean holographic phase, corresponding to the MIP of the stack, increases with increased doping, indicating the presence of trap states resulting in constant static in-built voltage. On other hand, we see a maximum in the holographic phase range with doping. This indicates that at very high doping, most substitutional P contribute to MIP, instead to built-in depletion potential, resulting in higher static charge compared to dynamic charge.