Passivated Contact Solar Cells Research Articles

Intrinsic Poly-Si layer thickness: Its role in pinhole contact formation and interface passivation in poly-silicon on oxide solar cells

Tunnel oxide passivating contact (TOPCon) solar cells are characterized by high surface passivation and electrical transport efficiency due to the chemical passivation and field effect of the tunnel oxide and doped poly-silicon layers, respectively. Nevertheless, the passivation quality, implied open-circuit voltage (iVoc), and device lifetime are adversely affected by high-temperature processing, leading to Auger recombination and pinhole defects in the tunnel oxide layer. This study aimed to explore the introduction of intrinsic poly-silicon as an interlayer to improve thermal stability and assesses its effect on the passivation of the tunnel oxide interface. Findings indicate that an intrinsic poly-silicon interlayer with a minimum thickness of 18 nm prevents passivation degradation at elevated temperatures. Additionally, the incorporation of this interlayer facilitates the tuning of the doping profile in crystalline silicon, resulting in a diminished pinhole density and an enhanced iVoc of 714.9 mV. These results advance our understanding of TOPCon solar cell performance and provide a foundation for their further optimization.

Tunnel silicon oxynitride phase transformation for n-type polysilicon passivating contacts in crystalline silicon solar cells

The study investigates the fabrication and characterization of tunnel oxynitride (TON) layers produced using Plasma-Enhanced Chemical Vapor Deposition (PECVD) at different pressure and power variations. The aim is to explore TON layers as potential substitutes for conventional SiO2 in Tunnel Oxide Passivated Contact (TOPCon) solar cells. Foe this purpose, an effective oxide thickness (EOT) of 1.1–1.2 nm and 1.5–1.6 nm has been achieved by treating the TON samples with NH3 and N2 gas plasma, respectively. Fourier Transform Infrared Spectroscopy (FTIR) analysis revealed critical variations in the chemical bonding within TON layers, which exhibit different properties based on the deposition conditions. The presence of nitrogen-nitrogen and nitrogen–hydrogen bonds is prominently influenced by changes in the PECVD parameters, directly affecting the layer’s optical and electronic properties. Notably, the presence of hydroxyl (O–H) and amino (NH2) groups within the TON structure suggests an improvement in surface passivation, essential for optimizing solar cell performance and durability. A lifetime of 737 and 823 μs has been recorded for N2 and NH3 samples, compared to the NAOS 710 μs reference sample. NH3 plasma-treated samples show an improved iVoc of 736 mV, indicating better phase transformation and passivation quality than N2 plasma treatment and the NAOS reference sample.

22.56% total area efficiency of n-TOPCon solar cell with screen-printed Al paste

Screen-printing Ag paste on the rear side of the Tunnel Oxide Passivated Contact solar cells (TOPCon) is still the mainstream method to form electrodes. However, the high price of precious metals increases the cost of TOPCon cells. Al is a cheap and high-performance conductor, and its work function is compatible with the rear side of TOPCon cells. In this study, we used a UV pulse laser (355 nm, 10 ps) to ablate the rear side SiNx passivation layer of TOPCon cells and then printed Al paste with different weight percentages of silicon (Si-wt.%) on the phosphorus-doped polycrystalline silicon (n+-poly-Si) layer to reduce the cost. We investigated the damage mechanism of laser on SiOx/n+-poly-Si/SiNx passivation structure and the contact mechanism between Al paste and n+-poly-Si layer. The results show that the Voc of SiOx/n+-poly-Si/SiNx passivation structure reduced about 6–7 mV when the laser energy density was 0.431 J/cm2. We got the best electrical performance of TOPCon cells printed with Al paste (25 wt%-29 wt% silicon). The open-circuit voltage (Voc) and the conversion efficiency (Eff), have reached 663.60 mV and 22.56 % respectively. Although the efficiency was 9.40 % relative lower than that of TOPCon cells printed with Ag paste, but the cost of Al paste only accounted for 10 % of Ag paste. In the future, the highest Eff of TOPCon solar cells printed with Al paste on the rear side are expected to reach the commercial TOPCon based on Ag paste, which applies laser doping selective emitter technology (SE) and bifacial poly-Si passivation structure.

Continuous distribution of interface states in n-type double-side poly-Si/SiOx passivating contact solar cells

Advanced passivation contact in high-efficiency silicon solar cells plays an important role for the sake of minimizing recombination losses. A stack of heavily doped polycrystalline silicon (poly-Si) and tunnel SiOx contact has attracted much attention, benefitting from its excellent characteristics of carrier selectivity and passivation, and which has been successfully applied in double-side poly-Si/SiOx passivating contact solar cells. Note that characteristics analysis of defects at tunnel SiOx/c-Si (crystalline silicon) interface remains an issue of concern. Herein, we observe capacitance transient spectroscopy arise from both electron and hole traps in the passivating contact structure of poly-Si(p+)/tunnel SiOx/c-Si(n). Subsequently, we propose a skillful procedure of deep-level transient spectroscopy (DLTS) measurement to confirm that the observed electron and hole traps are located at the tunnel SiOx/c-Si interface but not in the bulk of the c-Si substrate. Finally, we show a clear physical picture of continuous energy distribution for interface states.

Enhanced Passivation Effect of Tunnel Oxide Prepared by Ozone‐Gas Oxidation (OGO) for n‐Type Polysilicon Passivated Contact (TOPCon) Solar Cells

Nowadays, a stack of heavily doped polysilicon (poly‐Si) and tunnel oxide (SiOx) is widely employed to improve the passivation performance in n‐type tunnel oxide passivated contact (TOPCon) silicon solar cells. In this case, it is critical to develop an in‐line advanced fabrication process capable of producing high‐quality tunnel SiOx. Herein, an in‐line ozone‐gas oxidation (OGO) process to prepare the tunnel SiOx is proposed to be applied in n‐type TOPCon solar cell fabrication, which has obtained better performance compared with previously reported in‐line plasma‐assisted N2O oxidation (PANO) process. In order to explore the underlying mechanism, the electrical properties of the OGO and PANO tunnel SiOx are analyzed by deep‐level transient spectroscopy technology. Notably, continuous interface states in the band gap are detected for OGO tunnel SiOx, with the interface state densities (Dit) of 1.2 × 1012–3.6 × 1012 cm−2 eV−1 distributed in Ev + (0.15–0.40) eV, which is significantly lower than PANO tunnel SiOx. Furthermore, X‐ray photoelectron spectroscopy analysis indicate that the percentage of SiO2 (Si4+) in OGO tunnel SiOx is higher than which in PANO tunnel SiOx. Therefore, we ascribe the lower Dit to the good inhibitory effects on the formation of low‐valent silicon oxides during the OGO process. In a nutshell, OGO tunnel SiOx has a great potential to be applied in n‐type TOPCon silicon solar cell, which may be available for global photovoltaics industry.

Improving the performance of industrial TOPCon solar cells through the insertion of intrinsic a-Si layer

Passivating contact solar cells have gradually become the mainstream cell technology due to their excellent performance, and further improving the conversion efficiency has become a focus of subsequent research. Typically, achieving excellent field-effect passivation and low contact resistivity in doped polycrystalline silicon (poly-Si) requires heavy phosphorus doping. However, this approach can lead to a predicament wherein excessive phosphorus diffuses into the silicon (Si) substrate during annealing, consequently causing recombination losses. In response to this challenge, a structure incorporating an intrinsic amorphous silicon (a-Si (i)) layer within the passivation layers has been introduced. The primary objective of this structure is to retard the diffusion of phosphorus into the Si substrate. This study entails comprehensive characterizations to delve into the underlying mechanisms of films with the integrated a-Si (i) layer, including surface microscopy, active dopants profile, crystallographic structure, elemental distribution, and electrical properties. Finally, we have fabricated the industrial-sized TOPCon solar cells with an average efficiency of 23.83 %, which is 0.25 % higher than that of Baseline counterparts (23.58 %) on the production line. The above results have demonstrated the introduction of a-Si (i) film can be a buffer layer, retarding the diffusion of phosphorus into the Si substrate and obtaining a better passivation effect, enabling us to further tailor the doping profile for high-efficiency solar cells. Our work highlights a promising strategy to improve the performance of TOPCon solar cells, showcasing the substantial potential for implementation in industrial manufacturing.

Effects on Metallization of n+-Poly-Si Layer for N-Type Tunnel Oxide Passivated Contact Solar Cells.

Thin polysilicon (poly-Si)-based passivating contacts can reduce parasitic absorption and the cost of n-TOPCon solar cells. Herein, n+-poly-Si layers with thicknesses of 30~100 nm were fabricated by low-pressure chemical vapor deposition (LPCVD) to create passivating contacts. We investigated the effect of n+-poly-Si layer thickness on the microstructure of the metallization contact formation, passivation, and electronic performance of n-TOPCon solar cells. The thickness of the poly-Si layer significantly affected the passivation of metallization-induced recombination under the metal contact (J0,metal) and the contact resistivity (ρc) of the cells. However, it had a minimal impact on the short-circuit current density (Jsc), which was primarily associated with corroded silver (Ag) at depths of the n+-poly-Si layer exceeding 40 nm. We introduced a thin n+-poly-Si layer with a thickness of 70 nm and a surface concentration of 5 × 1020 atoms/cm3. This layer can meet the requirements for low J0,metal and ρc values, leading to an increase in conversion efficiency of 25.65%. This optimized process of depositing a phosphorus-doped poly-Si layer can be commercially applied in photovoltaics to reduce processing times and lower costs.

Laser ablation of thin SiN x layer coated on silicon wafer—evaluation of process performance for PERC solar cell application

In fabricating passivated emitter and rear contact (PERC) solar cells, creating small openings on the SiN x coated silicon substrate to establish metal contacts necessitates using a nanosecond pulsed green laser for ablation. However, the thermal nature of laser ablation poses a challenge. Excessive nitrogen diffusion from SiN x into the silicon substrate can compromise the electrical performance of solar cells. Therefore, this study aims to comprehensively understand how laser parameters impact the electrical properties of such solar cells. PERC solar cell precursors were initially fabricated by ablating the SiN x layer at four laser fluences, each corresponding to different regimes: solid, liquid, vapor, and phase explosion. Subsequently, various optical, chemical, and electrical characterizations were conducted on the solar cell precursors. Complete PERC solar cells were also fabricated to measure quantum efficiency (QE). In the solid regime, SiN x removal is precise, with minimal thermal damage, resulting in a nitrogen concentration of approximately 0.15%. Photoluminescence count and carrier lifetime are notably higher by 21% in the solid regime compared to the explosive regime. The QE measurement at 984 nm quantitatively assesses rear-side recombination losses. Notably, 26% of the area exhibits a 56% QE in the solid state, while this number drops to around 22% in the explosive state. This decline can be attributed to increased thermal damage in the explosive regime, which augments recombination centers and diminishes the solar cell performance. PERC solar cells ablated in the solid regime showcase lower subsurface damage, superior electrical characteristics, and higher performance than those ablated in the explosive regime.

Progress in TOPCon solar cell technology: Investigating hafnium oxide through simulation

In the realm of solar energy technology, exploring hafnium oxide (HfO2) in Tunnel Oxide Passivated Contact (TOPCon) solar cells is pivotal. This study delineates HfO2's evolution from semiconductor applications, highlighting its crucial role in enhancing TOPCon solar cell performance. Utilizing ATLAS Silvaco software, the study anticipates a 21.3% increase in charge carrier lifetime through optimized HfO2 layers, addressing challenges in interface engineering and scalability. Innovative research integrates hafnium oxide (HfO2) into TOPCon solar cells, marking a leap in photovoltaic technology. Utilizing ATLAS Silvaco simulations, it shows that HfO2 layers can significantly enhance cell performance, increasing charge carrier lifetime by 21.3% and potentially boosting efficiency by 25%. This underscores HfO2's advantages, like a higher dielectric constant and thermal stability, in improving solar cell efficiency and durability. Future efforts target refining deposition processes, projecting a 25% boost in overall power conversion efficiency (PCE). Emphasizing HfO2's significance in solar cell technology, this research contributes to global sustainable energy initiatives. Integrating HfO2 in TOPCon solar cells signifies a key achievement in harnessing clean, renewable energy. Upcoming research focuses on experimental validation, interface engineering, optimization, stability assessments, scalability, and collaborative studies, aiming to leverage HfO2's potential for elevating solar energy conversion technologies.

Low-temperature fabrication of boron-doped amorphous silicon passivating contact as a local selective emitter for high-efficiency n-type TOPCon solar cells

Tunnel oxide passivating contact (TOPCon) solar cells (SCs) currently dominate the photovoltaic industry but grapple with efficiency challenges. A primary concern is the direct contact between front-sided metal electrodes and boron emitters, resulting in substantial carrier recombination losses and limiting further efficiency improvements. Here, we introduce a low-temperature approach to deposit a local boron-doped amorphous silicon [a-Si:H(p)] between front-sided metal electrodes and boron emitters. This method, avoiding issues associated with high-temperature processes, demonstrates excellent passivation and contact properties, featuring the lowest contact resistivity (< 1 mΩ·cm2) and a low saturation current density (< 400 fA/cm2). The outstanding passivation and contact properties remain robust even with variations in diborane flow rates during a-Si:H(p) fabrication, annealing temperatures, and sheet resistances of boron emitters. We elucidate the factors contributing to the enhanced passivation observed in boron emitters with a-Si:H(p) through a combination of simulations and experiments. The a-Si:H(p) layer between boron emitters and metal electrodes acts as a protective barrier, preventing the diffusion of metal atoms and suppressing carrier recombination. A heterojunction is formed between a-Si:H(p) and the boron emitter, facilitating electric-field passivation. Consequently, the TOPCon SCs incorporating a-Si:H(p) achieve an efficiency of 24.50%, surpassing their counterparts without a-Si:H(p) (23.11%). This work utilizes low-temperature technology to achieve fully passivated contact, providing insights for the development of high-efficiency TOPCon SCs.

Towards &gt;25% Efficiency of Passivating-Contact Solar Cells in Mass Production

We report efficiencies of &gt;24% being consistently achieved in mass-production of passivating-contact solar cells. Furthermore, the certified efficiency of cells from our pilot line has reached 25.3% with 730 mV open-circuit voltage. An analysis of the cell performance, including simulations, shows that the cells’ rear-side is nearly ideal, while there remains potential for further optimization of the front emitter and passivation.

Data-Driven Tunnel Oxide Passivated Contact Solar Cell Performance Analysis Using Machine Learning.

Tunnel oxide passivated contacts (TOPCon) have gained interest as a way to increase the energy conversion efficiency of silicon solar cells, and the International Technology Roadmap of Photovoltaics forecasts TOPCon to become an important technology despite a few remaining challenges. To review the recent development of TOPCon cells, this work has compiled a dataset of all device data found in current literature, which sums up to 405 devices from 131 papers. This may seem like a surprisingly small number of cells given the recent interest in the TOPCon architecture, but it illustrates a problem of data dissemination in the field. Notwithstanding the limited number of cells, there is a great diversity in cell manufacturing procedures, and this work observes a gradual increase in performance indicating that the field has not yet converged on a set of best practices. By analyzing the data using statistical methods and machine learning (ML) algorithms, this work is able to reinforces some commonly held hypotheses related to the performance differences between different device architectures. This work also identifies a few more unintuitive feature combinations that would be of interest for further experimentally studies. This work also aims to inspire improvements in data management and dissemination within the TOPCon community.

AFORS-HET-based numerical exploration of tunnel oxide passivated contact solar cells incorporating n- and p-type silicon substrates.

The development of a tunnel oxide interfacial layer capped by a highly doped poly-Si layer is considered one of the most promising methods to reduce charge carrier recombination and improve the performance of conventional PERC devices. The thickness and doping concentration of emitters and BSF layers greatly influence the tunnelling current in TOPCon devices. In this research, we evaluated the performance of tunnel oxide passivated contact (TOPCon) solar cells by conducting an in-depth analysis of various key parameters. The parameter include the type of silicon substrate (n or p-type); the thickness and doping density (N a/N d) of n, n+, p, and p+ layers; and surface recombination velocity (front/rear), which were analyzed using AFORS-HET simulation software. A comparative analysis of performance demonstrates that the highest efficiency is achieved in the n-TOPCon solar cell with the following values: V oc = 660.2 mV, J sc = 45.05 mA cm-2, FF = 82.87%, and PCE = 25.74%. In the optimized p-TOPCon solar cell, the open circuit voltage (V oc) and fill factor (FF) exhibit improvements of 35.9 mV and 0.39%, respectively. However, the values of J sc and PCE decrease by 6.44 mA cm-2 and 2.2%, respectively, in p-TOPCon solar cells. Furthermore, photo-electroluminescence analysis reveals that the n-TOPCon solar cells exhibit a higher maximum photon flux (front/rear) than p-TOPCon solar cells.

Enhancement of efficiency in monocrystalline silicon solar cells

As the representative of the first generation of solar cells, crystalline silicon solar cells still dominate the photovoltaic market, including monocrystalline and polycrystalline silicon cells. With the development of silicon materials and cut-silicon wafer technologies, monocrystalline products have become more cost-effective, accelerating the replacement of polycrystalline products. In addition, the conversion efficiency of monocrystalline products increases gradually through high-efficiency cell technologies such as Passivated Emitter and Rear Cell (PERC). This paper will start with the solar cell efficiency and combine cost factor, the P-type PERC cell and additional four types of high-efficiency N-type cell technologies to improve the conversion efficiency for exploration, and will analyze and predict the future solar cell industrialization technologies. The study finally concludes that the N-type Tunnel Oxide Passivated Contact solar cell technology has a large industrial potential and could become a mainstream technology after the perc cell technology. At the same time, Interdigitated back contact cell structure and selective all-passive contact technologies are reliable paths to obtain solar cells with high conversion efficiency, integrated cost, and efficiency, depending on the advantages and compatibility of various cells. It can create conditions for the industrialization of low- cost and high-efficiency monocrystalline silicon solar cells.

Ultra-thin silicon oxide tunnel layer passivated contacts for screen-printed n-type industry solar cells

Effects of the ultra-thin silicon oxide (SiOx) on tunnel oxide passivated contact solar cells (TOPCon) are investigated in this paper. The experiment is fabricated to study the TOPCon electrical performance with different SiOx thickness and the champion efficiency is achieved by the TOPCon with a 1.5 nm SiOx layer, with Voc 698.93 mV, Jsc 40.14 mA/cm2, FF 81.03 and efficiency 22.73 %. For futher understanding, EDNA2 and AFORS-HET are used to simulate the relationship between the SiOx thickness, rear SRV and the doping concentration in n+ layer. It indicates that the total J0 at the SiOx-(c-Si) interface (J0, interface) can be affected by the phosphorus concentration at the SiOx-(c-Si) interface. Besides, due to the variation of SRV or P-doped concentration, different recombination mechanisms, including auger recombination and surface recombination, will dominant the total J0, interface. In addition, the sensitivity of TOPCon solar cells electrical performance to SiOx thickness can be affected by rear SRV, and the sensitivity of TOPCon solar cells electrical performance to rear SRV can be affected by SiOx thickness.

Effects of LPCVD-deposited thin intrinsic silicon films on the performance of boron-doped polycrystalline silicon passivating contacts

Highly efficient n-type tunnelling oxide passivated contact solar cells can be realized by integrating p-type polycrystalline silicon (p+ poly-Si) boron (B) diffusion technology. In this study, the intrinsic silicon (i-Si) film was prepared with varying crystalline states, by precisely controlling the deposition temperature using low-pressure chemical vapor deposition (LPCVD). The i-Si films transitioned from amorphous to polycrystalline when the deposition temperature was increased from 560 °C to 590 °C, with the crystallization rate increasing from 0 % to 81.5 %. An inverse correlation was observed between the electrical properties of B-diffused p+ poly-Si and the crystallization rate of i-Si thin films. The crystal structure of p+ poly-Si contained an amorphous phase, even after high-temperature B diffusion (>900 °C).The defect density and grain boundary potential barriers within the crystal were increased, which resulted in enhanced carrier scattering probability and deteriorated material performance. Amorphous silicon film deposited at lower temperatures can achieve low contact resistivity (ρc = 0.81 mΩ·cm2) and improved passivation performance (Δi-Voc > 10 mV) after B diffusion. These results have significant implications for the development of highly efficient passivated contact solar cells with excellent passivation performance and low contact resistance hole-selective contacts.

Design Rule of Electron- and Hole-Selective Contacts for Polycrystalline Silicon-Based Passivating Contact Solar Cells.

A crystalline silicon (c-Si) solar cell with a polycrystalline silicon/SiOx (poly-Si/SiOx) structure, incorporating both electron and hole contacts, is an attractive choice for achieving ideal carrier selectivity and serving as a fundamental component in high-efficiency perovskite/Si tandem and interdigitated back-contact solar cells. However, our understanding of the carrier transport mechanism of hole contacts remains limited owing to insufficient studies dedicated to its investigation. There is also a lack of comparative studies on the poly-Si/SiOx electron and hole contacts for ideal carrier-selective solar cells. Therefore, this study aims to address these knowledge gaps by exploring the relationship among microstructural evolution, dopant in-diffusion, and the resulting carrier transport mechanism in both the electron and hole contacts of poly-Si/SiOx solar cells. Electron (n+ poly-Si/SiOx/substrate)- and hole (p+ poly-Si/SiOx/substrate)-selective passivating contacts are subjected to thermal annealing. Changes in the passivation properties and carrier transport mechanisms of these contacts are investigated during thermal annealing at various temperatures. Notably, the results demonstrate that the passivation properties and carrier transport mechanisms are strongly influenced by the microstructural evolution of the poly-Si/SiOx layer stack and dopant in-diffusion. Furthermore, electron and hole contacts exhibit common behaviors regarding microstructural evolution and dopant in-diffusion. However, the hole contacts exhibit relatively inferior electrical properties overall, mainly because both the SiOx interface and the p+ poly-Si are found to be highly defective. Moreover, boron in the hole contacts diffuses deeper than phosphorus in the electron contacts, resulting in deteriorated carrier collection. The experimental results are also supported by device simulation. Based on these findings, design rules are suggested for both electron and hole contacts, such as using thicker SiOx and/or annealing the solar cell at a temperature not exceeding the critical annealing temperature of the hole contacts.

Regionalizing Nitrogen Doping of Polysilicon Films Enabling High-Efficiency Tunnel Oxide Passivating Contact Silicon Solar Cells.

Tunnel oxide passivating contact (TOPCon) solar cells (SCs) as one of the most competitive crystalline silicon (c-Si) technologies for the TW-scaled photovoltaic (PV) market require higher passivation performance to further improve their device efficiencies. Here, the successful construction of a double-layered polycrystalline silicon (poly-Si) TOPCon structure is reported using an in situ nitrogen (N)-doped poly-Si covered by a normal poly-Si, which achieves excellent passivation and contact properties simultaneously. The new design exhibits the highest implied open-circuit voltage of 755mV and the lowest single-sided recombination current density (J0 ) of ≈0.7 fAcm⁻2 for a TOPCon structure and a low contact resistivity of less than 5 mΩ·cm2 , resulting in a high selectivity factor of ≈16. The mechanisms of passivation improvement are disclosed, which suggest that the introduction of N atoms into poly-Si restrains H overflow by forming stronger Si-N and N-H bonds, reduces interfacial defects, and induces favorable energy bending. Proof-of-concept TOPCon SCs with such a design receive a remarkable certified efficiency of 25.53%.

24.7% industrial tunnel oxide passivated contact solar cells prepared through tube PECVD integrating with plasma-assisted oxygen oxidation and in-situ doped polysilicon

Tunnel oxide passivated contact (TOPCon) solar cells have gradually dominated the industrial silicon solar cells. In this paper, we have adopted the tube plasma-enhanced chemical vapor deposition (PECVD) technology integrating with nano SiOx (Tox) and in-situ phosphorus-doped polysilicon (n + poly-Si), in which Tox is prepared by plasma-assisted oxygen (O2) oxidation. Passivation and contact performance of TOPCon solar cells have been investigated under different thicknesses of Tox, and the following simulation has confirmed the optimal electrical properties, i.e., the implied open-circuit voltage (iVOC) of the hydrogenated lifetime sample is promoted to more than 736.1 mV on the textured wafer, corresponding to a lowest single-sided saturation current density (J0) of 4.6 fA/cm2, and the contact resistivity of 1.55 mΩ cm2 extracted from the transmission line method. Characterizations are carried out to conform the rear stack passivation layers satisfy the requirement of the high-efficiency TOPCon solar cells. Finally, we have fabricated the large-sized TOPCon solar cells with an average efficiency of 24.5% and a maximum efficiency of 24.7%, respectively. The above work has demonstrated the tube PECVD technology integrating with plasma-assisted O2 oxidation and in-situ doped poly-Si has the potential for the mass-production TOPCon in industry.

Laser Activation for Highly Boron-Doped Passivated Contacts

Passivated, selective contacts in silicon solar cells consist of a double layer of highly doped polycrystalline silicon (poly Si) and thin interfacial silicon dioxide (SiO2). This design concept allows for the highest efficiencies. Here, we report on a selective laser activation process, resulting in highly doped p++-type poly Si on top of the SiO2. In this double-layer structure, the p++-poly Si layer serves as a layer for transporting the generated holes from the bulk to a metal contact and, therefore, needs to be highly conductive for holes. High boron-doping of the poly Si layers is one approach to establish the desired high conductivity. In a laser activation step, a laser pulse melts the poly Si layer, and subsequent rapid cooling of the Si melt enables electrically active boron concentrations exceeding the solid solubility limit. In addition to the high conductivity, the high active boron concentration in the poly Si layer allows maskless patterning of p++-poly Si/SiO2 layers by providing an etch stop layer in the Si etchant solution, which results in a locally structured p++-poly Si/SiO2 after the etching process. The challenge in the laser activation technique is not to destroy the thin SiO2, which necessitates fine tuning of the laser process. In order to find the optimal processing window, we test laser pulse energy densities (Hp) in a broad range of 0.7 J/cm2 ≤ Hp ≤ 5 J/cm2 on poly Si layers with two different thicknesses dpoly Si,1 = 155 nm and dpoly Si,2 = 264 nm. Finally, the processing window 2.8 J/cm2≤ Hp ≤ 4 J/cm2 leads to the highest sheet conductance (Gsh) without destroying the SiO2 for both poly Si layer thicknesses. For both tested poly Si layers, the majority of the symmetric lifetime samples processed using these Hp achieve a good passivation quality with a high implied open circuit voltage (iVOC) and a low saturation current density (J0). The best sample achieves iVOC = 722 mV and J0 = 6.7 fA/cm2 per side. This low surface recombination current density, together with the accompanying measurements of the doping profiles, suggests that the SiO2 is not damaged during the laser process. We also observe that the passivation quality is independent of the tested poly Si layer thicknesses. The findings of this study show that laser-activated p++-poly Si/SiO2 are not only suitable for integration into advanced passivated contact solar cells, but also offer the possibility of maskless patterning of these stacks, substantially simplifying such solar cell production.