Halide Perovskite Photodiode Integrated CMOS Imager

Thin film photodiodes (TFPD) can supplement complementary metal-oxide-semiconductor (CMOS) image sensor vision by their exotic optoelectronic properties assisted by their monolithic processability. Halide perovskites are known to show outstanding optoelectronic properties, such as large absorption coefficient, long carrier diffusion lengths, and high carrier mobility, leading to high external quantum efficiency (EQE) and fast charge transport in photodiodes (PDs), especially compared with other thin-film photodiode candidates. In this paper, high-resolution two-dimensional (2D) and three-dimensional (3D) imaging capabilities are demonstrated using perovskite photodetection material with a silicon (Si) read-out integrated circuit (ROIC). The integration of this perovskite photodiode (PePD) on the Si ROIC provides fine resolution for 2D imaging. The fast carrier transport properties of the PePD enable depth sensing of objects using the same sensor. 3D imaging is demonstrated using the proposed top-electrode controlled indirect time-of-flight (iToF) operation supported by the fast PD switching through the top common electrode of the TFPD image sensor pixel. It is expected that the PePDs on Si ROIC could mark a significant milestone for the TFPD imaging platform with their outstanding optoelectronic performance in combination with the CMOS image sensor technology, not only for conventional 2D imaging but also by enabling extensions toward 3D sensing, promising applications in automotive, augmented reality (AR), and virtual reality (VR).