Simulation-based roadmap for the integration of poly-silicon on oxide contacts into screen-printed crystalline silicon solar cells

Abstract

We present a simulation-based study for identifying promising cell structures, which integrate poly-Si on oxide junctions into industrial crystalline silicon solar cells. The simulations use best-case measured input parameters to determine efficiency potentials. We also discuss the main challenges of industrially processing these structures. We find that structures based on p-type wafers in which the phosphorus diffusion is replaced by an n-type poly-Si on oxide junction (POLO) in combination with the conventional screen-printed and fired Al contacts show a high efficiency potential. The efficiency gains in comparsion to the 23.7% efficiency simulated for the PERC reference case are 1.0% for the POLO BJ (back junction) structure and 1.8% for the POLO IBC (interdigitated back contact) structure. The POLO BJ and the POLO IBC cells can be processed with lean process flows, which are built on major steps of the PERC process such as the screen-printed Al contacts and the $$\text{Al}_\text{2 }\text{O}_\text{3 }/\text{SiN }$$ Al 2 O 3 / SiN passivation. Cell concepts with contacts using poly-Si for both polarities ($$\text{POLO}^2$$ POLO 2 -concepts) show an even higher efficiency gain potential of 1.3% for a $$\text{POLO}^2$$ POLO 2 BJ cell and 2.2% for a $$\text{POLO}^2$$ POLO 2 IBC cell in comparison to PERC. For these structures further research on poly-Si structuring and screen-printing on p-type poly-Si is necessary.

Firing-Stable PECVD SiOxNy/n-Poly-Si Surface Passivation for Silicon Solar Cells

“…compared to industrial PERC+ solar cells. 7 Since all silicon solar cell designs require SiO x and doped poly-Si layers on one wafer side, single-sided deposition techniques such as PECVD are attractive because they eliminate the necessity of one-sided removal of the parasitic SiO x /poly-Si layer as in the case of double-sided LPCVD deposition processes. In addition, PECVD offers to combine the growth of the SiO x interface with the a-Si deposition in one process tool 25 as well as applying shadow masks for the local deposition of SiO x /a-Si fingers 31 as required for the POLO-IBC solar cell.…”

“…Passivating contacts based on SiO x /polysilicon (SiO x /poly-Si) layer stacks − are a promising technology for next-generation high-efficiency industrial silicon solar cells potentially succeeding mainstream passivated emitter and rear cells (PERCs) and bifacial PERC+ solar cells. , An outstanding passivation quality in combination with a good contact resistivity are the key advantages of SiO x /poly-Si contacts, which significantly reduce the recombination losses at metal fingers as well as of the phosphorus-doped emitter and hence exhibit a higher efficiency potential compared to presently around 23% efficient industrial PERC and PERC+ solar cells. − Solar cell efficiencies between 22.5 and 24.5% were demonstrated applying the SiO x /poly-Si contacts to industrial solar cell concepts such as tunnel oxide passivated contact (TOPCon), , monopoly, POLO-BJ, and POLO-IBC, whereas lab-type POLO2 IBC and TOPCon cells obtain up to 26.1% efficiency. The acronym polysilicon on oxide (POLO) stands for “poly-Si on oxide,” whereas TOPCon denotes “tunneling oxide passivating contact” .…”

“…To become economically attractive, the application of SiO x /poly-Si passivating contacts to industrial silicon solar cells requires the development of lean and hence cost-effective manufacturing process sequences, as the gain in conversion efficiency is only in the range of 0.5–2.0% abs. compared to industrial PERC+ solar cells . Since all silicon solar cell designs require SiO x and doped poly-Si layers on one wafer side, single-sided deposition techniques such as PECVD are attractive because they eliminate the necessity of one-sided removal of the parasitic SiO x /poly-Si layer as in the case of double-sided LPCVD deposition processes.…”

In Situ Reflectometry and Diffraction Investigation of the Multiscale Structure of p-Type Polysilicon Passivating Contacts for c-Si Solar Cells

“… 5 Due to its resilience at high temperatures, the poly-Si/SiO x contact promises compatibility with the mainstream metallization process currently used in the industry and thus a rapid increase of the c-Si solar cell efficiency beyond 24% in mass production. 5 − 7 …”

Numerical Modelling Analysis for Carrier Concentration Level Optimization of CdTe Heterojunction Thin Film–Based Solar Cell with Different Non-Toxic Metal Chalcogenide Buffer Layers Replacements: Using SCAPS-1D Software

“…The majority of the alternative materials were developed with the goal of producing low-cost, high-efficiency, and long-lasting solar cells. Although the efficiency is still modest, Nanostructured Metal Oxide Solar Cells have moved a step farther in delivering clean, cheap, and sustainable solar cells [1]. Solar energy conversion to useable power using a solid-state pn-junction based photovoltaic (PV) device offers enormous promise in the effort to reduce our current reliance on fossil fuels and, as a result, reduce harmful greenhouse gas emissions [2,3].…”