Mehul C. Raval

By Mehul C. Raval and Sukumar Madugula Reddy

The chapter will introduce industrial silicon solar cell manufacturing technologies with its current status. Commercial p-type and high efficiency n-type solar cell structures will be discussed and compared so that the reader can get a head-start in industrial solar cells. A brief over-view of various process steps from texturing to screen-printed metallization is presented. Texturing processes for mono-crystalline and multi-crystalline silicon wafers have been reviewed with the latest processes. An over-view of the thermal processes of diffusion and anti-reflective coating deposition has been presented. The well-established screen-printing process for solar cell metallization is introduced with the fast-firing step for sintering of the contacts. I-V testing of solar cells with various parameters for solar cell characterization is introduced. Latest developments in various processes and equipment manufacturing are also discussed along with the expected future trends.

Part of the book: Solar Cells

By Nagarajan Balaji, Mehul C. Raval and S. Saravanan

Solar cell market is led by silicon photovoltaics and holds around 92% of the total market. Silicon solar cell fabrication process involves several critical steps which affects cell efficiency to large extent. This includes surface texturization, diffusion, antireflective coatings, and contact metallization. Among the critical processes, metallization is more significant. By optimizing contact metallization, electrical and optical losses of the solar cells can be reduced or controlled. Conventional and advanced silicon solar cell processes are discussed briefly. Subsequently, different metallization technologies used for front contacts in conventional silicon solar cells such as screen printing and nickel/copper plating are reviewed in detail. Rear metallization is important to improve efficiency in passivated emitter rear contact cells and interdigitated back contact cells. Current models on local Al contact formation in passivated emitter rear contact (PERC) cells are reviewed, and the influence of process parameters on the formation of local Al contacts is discussed. Also, the contact mechanism and the influence of metal contacts in interdigitated back contact (IBC) cells are reviewed briefly. The research highlights on metallization of conventional screen printed solar cells are compared with PERC and IBC cells.

Part of the book: Solar Cells