Highly conductive and wide band gap amorphous-microcrystalline mixed-phase silicon films prepared by photochemical vapor deposition

Abstract

Doped hydrogenated amorphous‐microcrystalline mixed‐phase silicon (μc‐Si:H) films were prepared by the mercury photosensitized decomposition of a disilane‐hydrogen gas mixture, by adding phosphine and diborane for n and p type, respectively. The maximum dark conductivity and optical band gap of the films were, respectively, 20 S cm⁻¹ and ∼2.0 eV for n type, and 1 S cm⁻¹ and 2.3 eV for p type. It is most significant that the gaseous ratio of hydrogen to disilane should be enhanced up to 70 for n type, and even 300 for p type, to obtain such a highly conductive and wide gap film. The crystallinity of the photodeposited μc‐Si films appeared to be improved in comparison with that of films by conventional plasma glow discharge technique.