Characterization of post implantation annealing steps is done by extracting the activation and compensation data of implanted Al atoms. Usually, this is done by Hall measurements. The preparation of Hall samples and temperature dependent Hall measurements, however, are rather complex compared to, e.g., temperature dependent resistivity measurements by 4-point probing. Therefore, a model for extracting relevant electrical parameters from resistivity data has been developed. The model is based on the neutrality equation and a temperature dependent mobility model.