Supporting plasma processes for fabrication of n-doped nano-crystalline silicon thin film on low-cost glass substrates

Abstract Nano-crystalline silicon is an excellent material for applications in the optoelectronics industry. This intermediate material combines both the advantages of amorphous and crystalline silicon. However, the typical fabrication process of nano-crystalline silicon previously required high-quality substrates such as quartz or silicon wafers, which limited its potential applications. Recently, plasma treatments have been recognized as the most efficient and customizable methods for transforming materials. In this study, corona plasma was used to treat the low-cost glass substrates to improve their adhesion to silicon thin films. It allowed the film to become more uniform with a surface roughness of less than 10% at the thickness of about 1 micrometer. The conventional thermal annealing process was replaced by a high-power hydrogen plasma process, which does not cause harmful effects on the glass substrates and stimulates the amorphous-crystalline phase transition. The increasing of the crystalline fraction, which is known as the order of arrangement of silicon atoms network, affects the doped concentration as well as the electrical properties of the nc-Si:H thin films. The resulting n-doped nano-crystalline silicon thin film has a crystalline fraction of 32.8%, corresponding to a sheet resistance of 104 Ω/square.