Plasma Technology For Solar Cells

Abstract

Numerous low-temperature plasma sources and facilities, including capacitively coupled radiofrequency (RF) plasma-enhanced chemical vapor deposition (PECVD), microwave plasma (MP) CVD, and inductively coupled plasma (ICP) CVD, have been successfully utilized for the fabrication of photovoltaic (PV) devices, including bulk Silicon (Si) solar cells and thin-film Si solar cells. Low-temperature plasmas are primed to play a crucial part in creating a cleaner and more ecologically conscious world notably in developing PV power as a clean, sustainable energy source, with the growing consensus that climate change is unavoidable.In the case of bulk Si solar cells, plasma sources have a wide range of applications, including surface passivation through silicon nitride (SiNx:H) films (Schmidt, Peibst, & Brendel, 2018), plasma etching processes for eliminating parasitic emitters or phosphorus silicate glass (Rentsch,Schetter, Schlemm, Roth, & Preu, 2005), wafer cleaning (Lu, Koppes, & Bronsveld, 2018), and both masked and mask-free surface texturization (Moreno, Daineka, & Cabarrocas, 2010). However, practically most of the manufacturing operations for thin-film Si solar cells and HIT (heterojunction with intrinsic thin-layer) solar cells, including the fabrication of p-n junction, interface passivation, and surface texturing for light trapping, are carried out by applying plasma technologie In the process of low-temperature plasma generation, the degree of ionization is controlled by discharge parameters typically within 1026 1024 in capacitively coupled plasma (CCP) and could reach 1022 in high densityICP given by electron density 10111013 cm23 Jia, Saha, Ohse, & Shirai, (2006). Low ionization degree at low-temperature plasma got interest for material processing, taking advantage of lightweight electrons as compared with neutral gases, yet energy exchange between them becomes less efficient due to elastic collisions. Therefore, energetic electrons could possess high temperatures while neutral gas is maintained at ambient temperatures. These energetic electrons are likely advantageous for various elementary processes, including the dissociation of precursor molecules and the creation of free radicals