Bayesian Optimization for the Formation of Vertically Oriented Silicon Structures Using Langmuir–Blodgett Colloidal Lithography and Plasma Chemical Etching

In the semiconductor industry, lithography (patterning on substrates) and etching (transferring patterns onto substrates) are essential for the manufacturing of electronic devices. However, these processes require complex, costly equipment and numerous experiments to develop technologies that produce structures with precise geometric parameters. Finding more efficient and affordable methods for submicrometer-scale fabrication remains a pressing challenge. To address this, we propose a high-performance and cost-effective approach for creating vertically oriented silicon structures using Langmuir-Blodgett colloidal lithography combined with continuous ICP-RIE using SF₆/C₄F₈. We investigate the physicochemical mechanisms of plasma etching of latex spheres to achieve precise size reduction to the desired dimensions. Our work demonstrates the high efficiency of Bayesian optimization in developing continuous ICP-RIE processes for creating directional silicon structures, which are key components for vertical solar cells and gas sensors. Additionally, we demonstrate the potential to create silicon field-emission cathodes at the nanoscale without relying on traditional lithography.