[en] Because of the upgrade in the LHC (2020-2022), in which the luminosity is increased to above 5.10³⁴ cm^-2s^-1, in the CMS tracker a much higher radiation exposure than hitherto is to be expected. Therefore radiation-hardened sensors are required. For this reason in the framework of the Hamamatsu-Photonics-KK campaign among others Mpix sensors are studied. Furthermore they are tested concerning their material properties by characterizing befor and after the irradiation. Also the optimal geometry is searched for. This thesis studies two substrate types of the same thickness with two isolating mechanisms. Thereby also the influence of the geometry and different bias structures is regarded in order to draw conclusions on the radiation hardness.