In this study, the design, simulation, and fabrication of a betavoltaic battery for application in cardiac pacemaker power generators are investigated using Ni-63 and Sr-90 radioisotope sources in combination with silicon carbide (SiC) as the semiconductor material. Monte Carlo simulations were performed using the MCNPX code to determine the optimal semiconductor layer thickness and to evaluate the amount of energy deposited within each layer. Accordingly, a semiconductor layer thickness of 2 µm was identified as the optimal structure. The simulated electrical performance of the Ni-63 based device yielded a short-circuit current density of 19.2 nA/cm², an open-circuit voltage of 2.47 V, and an energy conversion efficiency of 35.5%. For the Sr-90 source, the corresponding values were obtained as a short-circuit current density of 126.25 nA/cm², an open-circuit voltage of 2.560 V, and an energy conversion efficiency of 1.8%, respectively.



During the fabrication stage, Doctor Blade and sputtering techniques were employed for layer deposition, and glass, aluminum, silicon wafer, and tungsten substrates were systematically examined. Overall, this work confirms that the combination of SiC semiconductor layers with Ni-63 and Sr-90 radioisotope sources, along with optimized layer thickness and appropriate substrate selection, enables the development of reliable betavoltaic batteries featuring high radiation safety, long operational lifespan, and elevated energy density, with initial potential for low-power applications, including cardiac pacemaker power generators.