Optimization of Phosphorus Emitter Formation from POCl3 Diffusion for p-Type Silicon Solar Cells Processing

Abstract

International audienceThe main purpose of this work is to demonstrate the possibility of diffusion process perfection during silicon solar cells manufacturing by CFD simulation. Presently, the major community of PV industries uses a p-type silicon solar cell as the starting material. In this work too, boron doped silicon wafers are considered to form solar cells. Likewise, phosphorus oxy-chloride (POCl3) is used as a precursor for phosphorus diffusion. To do this, we evaluate the throughput of an industrial low-pressure diffusion tube furnace in order to realize uniform emitters. The low-pressure tube furnace is designed to obtain emitter standard sheet resistances of about 60 Ω/sq and wafer uniformity less than 3 %. An up-to-date control model using for the first time a CFD numerical code has been derived from some previous work, to achieve better wafer to wafer temperature distribution. Moreover, a numerical process was built using an Atlas-Silvaco® TCAD Simulation Package where we can demonstrate that the short circuit current density (Isc) increases from 4.97 to 6.53 mA/cm2 compared to the conventional photovoltaic process. This (Isc) enhancement can be attributed to the strong temperature effect on furnace atmosphere. Our result proves that we can target electrical properties of an emitter only by the manipulation and optimization of the doping profile. This process refinement is expected to contribute in the development of high efficiency conventional crystalline silicon solar cells considered for mass production

Fabrication of Oxide Passivated and Antireflective Thin Film Coated Emitter Layer in Two Steps for the Application in Photovoltaic

“…The diffused wafers were dipped into hydrofluoric (HF) acid solution (HF49%: H2O=1:5) for 1 minute followed by rinsing in de-ionized water (DIW) and dried with nitrogen blow to remove the ARC layer, before the sheet resistivity data was taken. The sheet resistance of raw and phosphorus doped wafer was 115 Ω/square and 60 Ω/square, respectively 47) , which is also in well agreement with the other literatures published earlier for high efficiency silicon solar cells 10) . The solar cell fabricated in the same facility, was 9.63% efficient 48) following the similar diffusion process with a variation in the texturing, duration of diffusion, gas flow rate and process steps.…”

“…The developed simplified process explained in the other literature incorporates phosphorus diffusion 5) , ARC 6) and surface passivation 7) in a single step using the spin on dopant (SOD) process 8) . In commercial silicon solar cell fabrication process 9) , diffusion furnaces are widely used for the formation of the n-type emitter layer 10) . Low cost anti-reflection layer can be formed using chemical solution 11) , spray spin coated system 12) and sol-gel process 13) .…”

Micro-structured P–N junction surfaces: large-scale preparation, antifouling properties, and a synergistic antibacterial mechanism

“…2). The element diffusion technology 27,28 was then employed to fabricate a boron-doped n-type silicon (p + n-Si) wafer to form a p-n junction, which is beneficial for the directional transmission of charges from the material to the surface. A phosphorus-doped p-type silicon wafer (n + p-Si) was produced as well.…”

A Study on the Impact of PN-Junction Doping Concentration on the Efficiency of Monocrystalline Silicon Solar Cells

“…Researchers around the world have focused on silicon solar cells in recent years [1][2][3][4]. By exploiting all the possibilities of semiconductor technology, it is necessary to find a compromise between cost reduction and efficiency increase.…”