Doping Optimization of Solar Grade (SOG) Silicon Ingots for Increasing Ingot Yield and Cell Efficiency

Abstract

Образцы и методы исследованияИсследовали два вида ПК SoG: очищенный металлургиче-

The Possibility of Silicon Purification by Metallurgical Methods: Part I

“…Acid purification is very effective for transition metal impurities and less effective for doping impurities. According to our calculation and modelling of resistivity variation along the ingot's height, fully described in [19], the purity of the Si obtained after the final stage will be enough for further experimental work and can be used as a raw material for Si crystal growing by directional crystallization to obtain SoG-Si. In the next step, it is planned to run more detailed study of Si obtained after purification by directional crystallization method, namely, the production of test solar cells and a study of their specifications.…”

“…Namely, the slag refining method was used for purification. The Institute of Physics and Technology (Almaty, Kazakhstan) has conducted several studies on methods of metallurgical-grade silicon (MG-Si) production and purification of silicon to UMG-Si, as well as research on silane production methods [16][17][18][19][20][21][22]. As a result of previously conducted studies and works, purified silicon samples and Si crystals grown by the Czochralski method were obtained on a laboratory scale, approximately 2-3 kg.…”

“…Based on the results of the literature sources [23][24][25], as well as a number of our preliminary research concerning this topic [16][17][18][19][20][21][22], further development and improvement of technologies for obtaining and refining Si to solar quality is promising and of strategic importance for the Si industry of Kazakhstan.…”

“…The remaining transition metal impurities have segregation coefficients in the order of magnitude 10 −5 -10 −6 and therefore could be sufficiently well removed during the Si crystallization process. The sufficiently high phosphorus concentration can be compensated for by adding the gallium impurity without causing additional negative effects upon specifications of both Si and solar cells [19]. Various acids and parameters (temperature, duration etc.)…”

Integration of Kazakhstan Technologies for Silicon and Monosilane Production with the Suitable World Practices for the Production of Solar Cells and Panels

“…The KazPV Project is aimed at "Creating of the production of photovoltaic modules based on Kazakhstan silicon", which includes the production of MG-Si and solar-grade silicon (SoG-Si), solar cells, and photovoltaic modules. The first solar-grade silicon was obtained and test solar cells were created under KazPV project [5][6][7][8]. This initiative has not been completed yet, and it is planned to continue work in both directions, namely, silicon purification and growing Si ingots and producing solar cell.…”