Performance Enhancement of Tricalcium Phosphate Film for Bioelectronics with Bio-Friendly Supercritical Fluids Desorption Technology

In the rapidly advancing field of bioelectronics, searching for materials that combine superior insulating properties with biocompatibility is crucial, especially for implantable electronic devices. Traditional insulators in mature CMOS processes, though effective, lack biocompatibility, necessitating the exploration of alternative materials. This study introduces tricalcium phosphate (Ca₃(PO₄)₂), a primary component of human bones, and teeth, as an insulating layer material for the first time. High-quality, thickness-controlled Ca₃(PO₄)₂ films are fabricated using magnetron sputtering, and their electrical insulation, stability, and optical transparency have been thoroughly evaluated. To further optimize the insulation performance of Ca₃(PO₄)₂, particularly against residual impurities, and fabrication-induced defects, a bio-friendly low-temperature supercritical fluid desorption (LTSCF-Desorption) technique is developed, effectively removing impurities, repairing defects, and improving the interface states. After LTSCF-Desorption treatment, the leakage current of the Ca₃(PO₄)₂ films is reduced by 30%, along with the enhancements of the films' stability and transmittance. Further material analysis clarified the internal mechanisms behind the improvement of the Ca₃(PO₄)₂ films. Overall, this study not only broadens the application scenarios of Ca₃(PO₄)₂ in bioelectronics but also develops a bio-friendly supercritical desorption technique, providing a new pathway for optimizing the performance of bioelectronic devices and materials.