An SOI-Based Back-Junction Back-Contact Thin-Film Tritium Betavoltaic Cell with Interdigitated Electrodes

In this paper, an SOI-based back-junction back-contact (BJ-BC) thin-film tritium betavoltaic cell with interdigitated electrodes was demonstrated for the first time. The interdigitated electrodes are prepared on a 4 inch SOI wafer with a device layer thickness of 1.5 μm. The BJ-BC thin-film betavoltaic cell was obtained by releasing the device layer through back-side wet etching and buried oxide etching. The electrical characteristics of the BJ-BC thin-film betavoltaic cell were tested using the electron beam (E-beam) irradiation in a scanning electron microscope (SEM). Using 1.01nA E-beam of 5keV to simulate tritium sources as the test condition, the open circuit voltage of 0.24V, short current of 0.924uA, and energy conversion efficiency of 2.3% were achieved. The results indicated that this SOI-based BJ-BC thin-film tritium betavoltaic cell has a vast potential application in the future.