Process parameter selection study on SiNx:H films by PECVD method for silicon solar cells

• Relationship between parameters and quality indices of SiNx films is gained.
• Optimal process parameters are obtained by comprehensive scoring method.
• The chief influencing factor for the quality of SiNx films is Flow-Rate Ratio.
• The numerical model for the location of optimal process parameters is established.

Process parameter selection is a crucial step for SiNx:H film preparation process by Plasma Enhanced Chemical Vapor Deposition (PECVD) during the fabrication of silicon solar cells. Practically, process parameter selection lacks effective decision-making method and mostly relies on full-experiment-based judgments. Motivated by which, a holistic process parameter selection approach is proposed and established in this paper. The relationships between process parameters and every single quality evaluating index of SiNx:H films are figured out by the single factor experiment. Then the optimal process parameters are selected by the comprehensive scoring method. Meanwhile, a new mathematical model is employed to boost the optimal outputs of the orthogonal experiments to obtain the priority of the four input factors as: Flow-Rate Ratio of NH3/SiH4, Working Pressure, Substrate Temperature and Total Gas Flow Rate. Subsequently, the brief analysis is given to these input factors and quality evaluating indices. Finally, the effectiveness and efficiency of the proposed approach is elaborated both in technology and on cost reduction of mass production by a real case example in a photovoltaic manufacturer.