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1.
    
Ion implantation is a suitable and promising solution for the massive industrialization of boron doping, which is a crucial process step for most next‐generation solar cells based on crystalline silicon (c‐Si). However, the use of ion implantation for boron doping is limited by the high temperature (in the 1050°C range) of the subsequent activation anneal, which is essential to dissolve the boron clusters and reach a high‐emitter quality. In this work, we propose the use of plasma‐immersion ion implantation (PIII) from B2H6 gas precursor instead of the standard beamline ion implantation (BLII) technique to decrease this temperature down to 950°C. PIII and BLII boron emitters were compared with annealing temperatures ranging from 950°C to 1050°C. Contrary to BLII, no degradation of the emitter quality was observed with PIII implants annealed at 950°C along with a full activation of the dopants in the emitter. At 1000°C, emitter saturation current densities (J0e) below 21 fA/cm2 were obtained using the PIII technique regardless of the tested implantation doses for sheet resistances between 110 and 160 Ω/sq. After metallization steps, the metal/emitter contact resistances were assessed, indicating that these emitters were compatible with a conventional metallization by screen‐printing/firing. The PIII boron emitters' performances were further tested with their integration in n‐type passivated emitter rear totally diffused (PERT) solar cells fully doped by PIII. Promising results already show a conversion efficiency of 20.8% using a lower annealing temperature than with BLII and a reduced production cost.  相似文献   

2.
    
Ion implantation has the advantage of being a unidirectional doping technique. Unlike gaseous diffusion, this characteristic highlights strong possibilities to simplify solar cell process flows. The use of ion implantation doping for n‐type PERT bifacial solar cells is a promising process, but mainly if it goes with a unique co‐annealing step to activate both dopants and to grow a SiO2 passivation layer. To develop this process and our SONIA cells, we studied the impact of the annealing temperature and that of the passivation layers on the electrical quality of the implanted B‐emitter and P‐BSF. A high annealing temperature (above 1000 °C) was necessary to fully activate the boron atoms and to anneal the implantation damages. Low J0BSF (BSF contribution to the saturation current density) of 180 fA/cm2 was reached at this high temperature with the best SiO2 passivation layer. An average efficiency of 19.7% was reached using this simplified process flow (“co‐anneal process”) on large area (239 cm2) Cz solar cells. The efficiency was limited by a low FF, probably due to contaminations by metallization pastes. Improved performances were achieved in the case of a “separated anneals” process where the P‐BSF is activated at a lower temperature range. An average efficiency of 20.2% was obtained in this case, with a 20.3% certified cell. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

3.
    
The use of ion implantation doping instead of the standard gaseous diffusion is a promising way to simplify the fabrication process of silicon solar cells. However, difficulties to form high‐quality boron (B) implanted emitters are encountered when implantation doses suitable for the emitter formation are used. This is due to a more or less complete activation of Boron after thermal annealing. To have a better insight into the actual state of the B distributions, we analyze three different B emitters prepared on textured Si wafers: (1) a BCl3 diffused emitter and two B implanted emitters (fixed dose) annealed at (2) 950°C and at (3) 1050°C (less than an hour). Our investigations are in particular based on atom probe tomography, a technique able to explore 3D atomic distribution inside a material at nanometer scale. Atom probe tomography is employed here to characterize B atomic distribution inside textured Si solar cell emitters and to quantify clustering of B atoms. Here, we show that implanted emitters annealed at 950 °C present maximum clusters due to poor solubility at lower temperature and also highest emitter saturation current density (J0e = 1000 fA/cm2). Increasing the annealing temperature results in greatly improved J0e (131 fA/cm2) due to higher solubility and a consequently lower number of clusters. BCl3 diffused emitters do not contain any B clusters and presented the best emitter quality. From our results, we conclude that clustering of B atoms is the main reason behind higher J0e in the implanted boron emitters and hence degraded emitter quality. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

4.
    
In this work, we develop SiOx/poly‐Si carrier‐selective contacts grown by low‐pressure chemical vapor deposition and boron or phosphorus doped by ion implantation. We investigate their passivation properties on symmetric structures while varying the thickness of poly‐Si in a wide range (20‐250 nm). Dose and energy of implantation as well as temperature and time of annealing were optimized, achieving implied open‐circuit voltage well above 700 mV for electron‐selective contacts regardless the poly‐Si layer thickness. In case of hole‐selective contacts, the passivation quality decreases by thinning the poly‐Si layer. For both poly‐Si doping types, forming gas annealing helps to augment the passivation quality. The optimized doped poly‐Si layers are then implemented in c‐Si solar cells featuring SiO2/poly‐Si contacts with different polarities on both front and rear sides in a lean manufacturing process free from transparent conductive oxide (TCO). At cell level, open‐circuit voltage degrades when thinner p‐type poly‐Si layer is employed, while a consistent gain in short circuit current is measured when front poly‐Si thickness is thinned down from 250 to 35 nm (up to +4 mA/cm2). We circumvent this limitation by decoupling front and rear layer thickness obtaining, on one hand, reasonably high current (JSC‐EQE = 38.2 mA/cm2) and, on the other hand, relatively high VOC of approximately 690 mV. The best TCO‐free device using Ti‐seeded Cu‐plated front contact exhibits a fill factor of 75.2% and conversion efficiency of 19.6%.  相似文献   

5.
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Hyperdoping that introduces impurities with concentrations exceeding their equilibrium solubility has been attracting great interest since the tuning of semiconductor properties increasingly relies on extreme measures. In this review we focus on hyperdoped silicon (Si) by introducing methods used for the hyperdoping of Si such as ion implantation and laser doping, discussing the electrical and optical properties of hyperdoped bulk Si, Si nanocrystals, Si nanowires and Si films, and presenting the use of hyperdoped Si for devices like infrared photodetectors and solar cells. The perspectives of the development of hyperdoped Si are also provided.  相似文献   

6.
硼离子选择注入制备多孔硅微阵列   总被引：1，自引：0，他引：1  
根据 p型硅和 n型硅不同的制备多孔硅的工艺条件 ,利用硼离子选择注入 ,在 n型硅片上的局部微区域 ,形成易于腐蚀的 p型硅 ,用电化学腐蚀方法制备出图形化的多孔硅阵列 .省去了传统掩膜腐蚀工艺的掩膜材料的选取与制备以及后道工艺中掩膜材料的清除等工艺 ,克服了掩膜材料掩蔽效果较差以及存在横向钻蚀等缺点 .通过 AFM,SEM测试 ,证明该方法的效果很好  相似文献   

7.
We have demonstrated feasibility to form silicon-on-insulator (SOI) substrates using plasma immersion ion implantation (PIII) for both separation by implantation of oxygen and ion-cut. This high throughput technique can substantially lower the high cost of SOI substrates due to the simpler implanter design as well as ease of maintenance. For separation by plasma implantation of oxygen wafers, secondary ion mass spectrometry analysis and cross-sectional transmission electron micrographs show continuous buried oxide formation under a single-crystal silicon overlayer with sharp Si/SiO2 interfaces after oxygen plasma implantation and high-temperature (1300°C) annealing. Ion-cut SOI wafer fabrication technique is implemented for the first time using PIII. The hydrogen plasma can be optimized so that only one ion species is dominant in concentration and there are minimal effects by other residual ions on the ion-cut process. The physical mechanism of hydrogen induced silicon surface layer cleavage has been investigated. An ideal gas law model of the microcavity internal pressure combined with a two-dimensional finite element fracture mechanics model is used to approximate the fracture driving force which is sufficient to overcome the silicon fracture resistance.  相似文献   

8.
    
This paper shows for the first time a comparison of commercial‐ready n‐type passivated emitter , rear totally diffused solar cells with boron (B) emitters formed by spin‐on coating, screen printing, ion implantation, and atmospheric pressure chemical vapor deposition. All the B emitter technologies show nearly same efficiency of ~20%. The optimum front grid design (5 busbars and 100 gridlines), calculated by an analytical modeling, raised the baseline cell efficiency up to 20.5% because of reduced series resistance. Along with the five busbars, rear point contacts formed by laser ablation of dielectric and physical vapor deposition Al metallization resulted in another 0.4% improvement in efficiency. As a result, 20.9% efficient n‐type passivated emitter, rear totally diffused cell was achieved in this paper. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

9.
    
Increase in incident light and surface modification of the charge transport layer are powerful routes to achieve high-performance efficiency of perovskite solar cells (PSCs) by improving the short-circuit current density (JSC) and charge transport characteristics, respectively. However, few techniques are studied to reduce reflection loss and simultaneously improve the electrical performance of the electron transport layer (ETL). Herein, an inclined fluorine (F) sputtering process to fabricate high-performance PSCs is proposed. The proposed process simultaneously implements the antireflection effect of F coating and the effect of F doping on a TiO2 ETL, which increases the amount of light transmitted into the PSC due to the extremely low refractive index (≈1.39) and drastically improves the electrical properties of TiO2. Consequently, the JSC of the F coating and doping perovskite solar cell (F-PSC) increased from 25.05 to 26.01 mA cm−2, and the power conversion efficiency increased from 24.17% to 25.30%. The unencapsulated F-PSC exhibits enhanced air stability after 900 h of exposure to ambient environment atmosphere (30% relative humidity, 25 °C under dark condition). The inclined F sputtering process in this study can become a universal method for PSCs from the development stage to commercialization in the future.  相似文献   

10.
    
TOPCon (tunnel oxide passivated contact) solar cell is the mainstream high-efficiency crystalline silicon solar cell structure. However, the lack of efficient passivation contact mechanisms on the front surface restricts the electrical performance ability to improve further. Selective emitter (SE) technology, considered a potential solution, needs to be more mature. This work provides a unique thermal pre-diffusion approach combined with laser treatment and post-oxidation annealing to create SE structures in TOPCon solar cells. Times for the high-temperature process are equivalent to those for a traditional homogenous emitter. The innovative thermal pre-diffusion process created a unique boron doping profile, achieving a high surface concentration of nearly 1 × 1020 cm−3 with a shallow junction depth of approximately 0.25 μm. Laser treatment further activated boron and facilitated its diffusion, influenced by the boron silicate glass layer and surface boron atoms. Adjustments were made to improve the pre-diffusion recipe, including an additional boron deposition step, increasing non-activated boron atoms. Introducing larger pyramidal microstructures also improved the junction depth and surface concentration in the heavily doped region. Compared to homogeneous emitters, the SE structures exhibited lower surface concentration in the lightly doped region, reducing the recombination current density in the passivation region J0,pass values. The SE structures achieved higher junction depths, limiting metal atom diffusion and reducing the current recombination density in the metal contact region J0,metal values. The contact resistivity between metal and silicon was also decreased. Overall, introducing SE structures resulted in a batch-average efficiency improvement of 0.26%, reaching an average efficiency of 25.22% for TOPCon solar cells, and has industrial mass-producible.  相似文献   

11.
    
High and stable lifetimes recently reported for n‐type silicon materials are an important and promising prerequisite for innovative solar cells. To exploit the advantages of the excellent electrical properties of n‐type Si wafers for manufacturing simple and industrially feasible high‐efficiency solar cells, we focus on back junction n+np+ solar cells featuring an easy‐to‐fabricate full‐area screen‐printed aluminium‐alloyed rear p+ emitter. Independently confirmed record‐high efficiencies have been achieved on n‐type phosphorus‐doped Czochralski‐grown silicon material: 18·9% for laboratory‐type n+np+ solar cells (4 cm2) with shadow‐mask evaporated front contact grid and 17·0% for front and rear screen‐printed industrial‐type cells (100 cm2). The electrical cell parameters were found to be perfectly stable under illumination. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

12.
    
We present a detailed study on aluminum‐boron codoping of silicon by alloying from screen‐printed aluminum pastes containing boron additives (Al–B pastes). We derive an analytical model for the formation of the Al–B acceptor profiles by quantitatively describing (i) the composition of the Al–B–Si melt and (ii) the incorporation of Al and B acceptor atoms into the recrystallizing Si lattice. We show that measured Al–B dopant profiles can be excellently described by this model, which therefore offers a straightforward method for the comprehensive investigation of alloying from Al–B pastes. The formation of a characteristic kink in the Al–B dopant profile curve can thus be ascribed to the exhaustion of the B additive dissolution during alloying. By intentionally adding elemental B powder to an Al paste, we demonstrate that only a low percentage of the B powder actually dissolves into the melt. We show that this incomplete dissolution of the B additive strongly affects the recombination characteristics of Al–B–p+ regions and, thus, is an important element of alloying from Al–B pastes. This study therefore provides improved understanding of aluminum‐boron codoping of silicon. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

13.
本文制备了工业级纳米绒面多晶硅太阳电池,研究 了发射极扩散方阻对其光电转换 性能的影响。结果表明:提高发射极扩散方阻能够有效地提升电池的开路电压、短路电流, 但填充因子相对降低。通过分析关键光电参数,其原因归结为:提高发射极扩散方阻有利于 降低发射极及其表面载流子复合,但过高的发射极扩散方阻将导致发射极与金属栅线接触不 良。采用优化的发射极扩散方阻,纳米绒面相对于微米绒面多晶硅太阳电池具有改善的光电 转换性能,产线均值光电转换效率达到了19.20%。基于上述研究结果 ,讨论了进一步通过调控发射极扩散方阻来优化纳米绒面多晶硅太阳电池的方法。  相似文献   

14.
N型背发射极晶体硅太阳电池模拟研究   总被引：1，自引：0，他引：1  
N型晶体太阳电池由于少子寿命高、光致衰减低、弱光响应好等优点,近年来在高效率低成本太阳电池领域一直备受关注。利用PC1D模拟,对N型背发射极晶体硅太阳电池进行了分析。结果表明,背发射极掺杂浓度、结深、背表面复合速率、前表面掺杂浓度及复合速率都对电池转换效率有较大影响,尤其是电池前表面与背表面复合速率对电池性能的影响最为明显,而电池前表面场掺杂深度则对电池性能影响较小。对于前表面复合来说,当前表面复合速率小于1×103cm/s时,电池性能受表面复合速率变化的影响很小;但复合速率超过1×103cm/s后,电池转换效率快速下降。背表面复合对电池效率影响则更明显,当背表面复合速率超过1×104cm/s后,电池转换效率急剧下降,在背表面复合速率增大到1×106cm/s时,电池效率下降到不足5%,而在电池背表面复合速度较小时(10~103cm/s)则可获得较高的转换效率。  相似文献   

15.
    
B implanted emitters are investigated in the back junction cell configuration and their material properties are tested in double side implanted Si wafers. B has been implanted at 5 keV at various dose conditions varying from 1 × 1014 up to 3 × 1015 at./cm2 and activated at 1000°C for 10 min. N‐type 8 × 8 cm2 mono‐crystalline cells are fabricated and measured. Both fill factor and efficiency increase for high‐B doses. However, at 1015 at./cm2 B dose the Voc drops, which is in agreement with lifetime degradation in the wafer. Defect evolution simulations of BnIm clusters formation is correlated with lifetime degradation. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

16.
等离子体离子注入(PII)是一种用于材料表面改性的新型离子注入技术。PII分为两类,用于金属表面改性时称为等离子体源离子注入技术(PSII),用于半导体材料表面改性时称为等离子体浸没离子注入(PIII)。本文介绍一种新的PII技术,称为全方位离子注入(All Orientation Ion Implantation),采用横磁瓶电子迴旋共振等离子体源,样品上的负高压可以是直流、交流或脉冲方式,本装置可以工作在离子注入和动态离子束混合两种模式。  相似文献   

17.
单片Si-FED的结构和设计   总被引：1，自引：0，他引：1  
根据场发射显示器（ＦＥＤ）的工作原理和所要求的电学参数,利用常规的硅半导体工艺和微机械加工技术,设计和试制了显示面积为１０．８ｍｍ×１０．８ｍｍ的研究性器件。版图设计中采用了离子注入法形成导电网络结构和横向负反馈电阻。工艺流程采用了全干法两步刻蚀和热氧化增尖形成理想硅微尖锥的方案。硅场发射冷阴极阵列（Ｓｉ－ＦＥＣＡ）是ＦＥＤ的核心。  相似文献   

18.
    
This study focuses on the characterisation and the fabrication of solar cells using n‐type multicrystalline silicon purified via the metallurgical route. Electrical and chemical analyses were performed on wafers taken from several positions along the crystallised ingot. The impact of the fabrication processing steps was investigated via effective carrier lifetime measurements. Solar cells were processed, and their efficiencies were found to be dependent on the position of the wafer along the ingot height, that is, the wafer's resistivity. A maximum conversion efficiency of 15.0% was obtained on cells from the bottom part of the ingot. In this study, the minimum resistivity value of 0.4 Ω cm resistivity is given in order to reach adequate cell efficiency. Light‐soaking experiments were then performed on the fabricated cells. No significant variations of the cell performances were observed even after 110 h at 60 °C, meaning that the fabricated cells are stable under illumination. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

19.
    
This paper reports on the use of ultraviolet laser for forming segmented selective emitters on POCl 3 n + –p–p + solar cells. Laser scan speed, pulse power, and repetition rate are optimized to minimize laser‐induced defects, which are found to enhance recombination and reduce the local open‐circuit voltage. Laser‐doped selective emitters formed by locally driving in additional phosphorous from the diffusion glass are well suited for an etchback process without the need for a mask. In this paper, we show a novel selective emitter design that is segmented instead of continuous, combined with an emitter etchback process gives an efficiency improvement of about 0.3% absolute over a standard industrial type solar cell and 0.2% absolute improvement over a non‐segmented selective emitter solar cell. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

20.
    
Gapless interdigitated back contact (IBC) solar cells were fabricated with phosphorous back surface field on a boron emitter, using an ion implantation process. Boron emitter (boron ion implantation) is counter doped by the phosphorus back surface field (BSF) (phosphorus ion implantation) without gap. The gapless process step between the emitter and BSF was compared to existing IBC solar cell with gaps between emitters and BSFs obtained using diffusion processes. We optimized the doping process in the phosphorous BSF and boron emitter region, and the implied Voc and contact resistance relationship of the phosphorous and boron implantation dose in the counter doped region was analyzed. We confirmed the shunt resistance of the gapless IBC solar cells and the possibility of shunt behavior in gapless IBC solar cells. The highly doped counter doped BSF led to a controlled junction breakdown at high reverse bias voltages of around 7.5 V. After the doping region was optimized with the counter doped BSF and emitter, a large‐area (5 inch pseudo square) gapless IBC solar cell with a power conversion efficiency of 22.9% was made.  相似文献   

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