Ultra-Transparent Cerium-Doped Indium Oxide Films Deposited with Industry-Scale Reactive Plasma Deposition

Abstract

Transparent conductive oxide (TCO) films are widely used as electrodes in photovoltaic devices, such as perovskite solar cells and heterojunction solar cells. However, in the conventional physical vapor deposition process, there may be ion bombardment damage to the underlayer coatings, and high deposition temperature also have an adverse effect on perovskite and amorphous silicon layers during TCO deposition. Herein, reactive plasma deposition was effectively utilized for cerium-doped indium oxide (ICO) film as an ultra-transparent electrode. The effects of plasma gun current and the oxygen ratio on the optical and electrical properties, and also on the structure of the ICO films, were investigated. With an industry-scale reactive plasma deposition tool, an outcome of 140-nm ICO film can be achieved within 50 s, which represents a good throughput with the average growth rate of 2.8 nm/s. When the working current was 165 A and the oxygen ratio was 12%, the average transmittance of ICO films reached the highest value (93.09%) in the wavelength range of 400–1200 nm. The average transmittance in the visible wavelength range was 94.23%. The peak transmittance was up to 99.67% at 515 nm, and the corresponding resistivity was 4.68 × 10⁻⁴ Ω cm.