Optimized ALD-ZnO Thin Films for High-Performance 12 μm Pixel Microbolometers: Fabrication, Simulation, and Design Strategies for Infrared Sensing

A zinc oxide (ZnO)-based microbolometer with a 12 μm pixel pitch was developed using atomic layer deposition (ALD) on silica (SiO2/Si) substrates for infrared (IR) detection. ZnO offers a complementary metal-oxide semiconductor (CMOS)-compatible, thermally stable, low-cost alternative, unlike conventional bolometers. ZnO thin films were deposited via ALD on SiO2/Si substrates at 120, 150, and 200 °C for 1200, 1500, and 1800 cycles, respectively, and analyzed using various characterization techniques. The optimized ZnO thin film exhibited a −12.9 %/K temperature coefficient of resistance (TCR). Pixel design of all the films were carried out. Thermal modeling revealed a thermal conductance of 1.21 × 10–7 W/K and a time constant of 336 μs. The designed pixel achieved a responsivity of 1.10 × 108 V/W, noise equivalent power (NEP) of 4.13 × 10–14 W/√Hz, detectivity of 1.84 × 1014 cm·√Hz/W, and noise equivalent temperature difference (NETD) of 77.43 mK. These results demonstrate the potential of CMOS-compatible ALD-grown ZnO for high-performance microbolometric IR sensing.