This study explored the feasibility of employing metallic copper (Cu) as the cathode layer in tantalum electrolytic capacitors. The focus was on fabrication methods and performance testing of flat metal-insulator-metal (MIM) capacitors with a Ta/Ta2O5/Cu structure. An amorphous Ta2O5 thin film was deposited on Ta foil surfaces via anodization. Two Cu deposition techniques, namely chemical Cu plating and magnetron sputtering, were utilized to create the Ta/Ta2O5/Cu structures. These structures were subjected to extensive characterization and performance evaluation. The experimental results demonstrate the absence of capacitive characteristics in the Ta/Ta2O5/Cu structures fabricated via different Cu deposition methods during electrical performance testing, the resistance measured between the positive and negative electrodes was only 0.7Ω. And direct utilization of metallic Cu as the cathode layer in Ta capacitors leads to the oxidation of Cu into copper ions during the testing process,subsequently infiltrating the Ta2O5 dielectric layer and causing the breakdown of Ta2O5. Thus, it can be concluded that metallic Cu is unsuitable as a direct cathode layer in Ta capacitors