Deep-N-Well-Assisted CMOS Photovoltaic Micro-Cells for Powering the Wearable Sensors

This paper investigates the performance of small-area (0.8-1 mm²) silicon photovoltaic cells for powering wearable sensors. Achieving optimal performance under low-flux illumination with longer wavelengths is essential for such applications, but it is challenging for silicon cells due to shunt leakage and recombination losses. To address this, the study employs triple well Deep-N-Well-based on CMOS technology, resulting in demonstrated performance improvements. The measurement results of the I-V characteristics demonstrated an I_sc of approximately 140μA and a V_oc of 0.51 when illuminated with near-IR incident light. Furthermore, an in-depth analysis of the PV cell's optical and physical performance is conducted using the finite-element method (FEM), which aligns well with the practical characteristics observed in the PV cells. The results show improved power conversion efficiency under low illumination conditions in the near-infrared range, making them suitable for use in implantable devices.