Plasma Enhanced Chemical Vapor Deposition Deposition Research Articles

Phosphorus doped hydrogenated silicon oxycarbide: Film formation, properties and its application on silicon heterojunction solar cell

An ultrathin phosphorus doped hydrogenated microcrystalline silicon oxycarbide (n-μc-SiCO:H) layer deposited by plasma enhanced chemical vapor deposition (PECVD) method can be used as a window layer for silicon heterojunction solar cells. The optical and electrical properties of n-μc-SiCO:H films were controlled by PECVD deposition conditions. The interplay effects of H2, CO2 and PH3 to SiH4 gas ratio on the chemical composition, material structure and properties of n-μc-SiCO:H film were systematically determined. O, H, C and P atoms were observed to incorporate into the silicon network of n-μc-SiCO:H layer, while most of the atoms bond directly to Si atoms. Incorporation of oxygen and carbon atoms into n-μc-SiCO:H film, confirmed by XPS as formation of Si-O and Si-C bonds, enlarged the optical absorption band gap (Eg) value. Both film crystallinity and phosphorus concentration in n-μc-SiCO:H layer were observed to be controlled by the H2, CO2 and PH3 to SiH4 gas ratio. The electric performance of HJT solar cell was depended on the optical and electrical properties of n-μc-SiCO:H layer. An average efficiency (across ∼ 120 cells) of 26.32 % was achieved in cells with optimized deposition parameters for the n-μc-SiCO:H layer. The reaction gas ratio was also the dominant factor in determining the number and size of nanoscale Si crystallites embedded in the n-μc-SiCO:H layer. The conductivity of n-μc-SiCO:H layer was determined by the activated phosphorus concentration but independent of the total phosphorus concentration. It was also found that large concentrations of small Si crystallites of size less than 3 nm improved film conductivity.

An ultra high-endurance memristor using back-end-of-line amorphous SiC

Integrating resistive memory or neuromorphic memristors into mainstream silicon technology can be substantially facilitated if the memories are built in the back-end-of-line (BEOL) and stacked directly above the logic circuitries. Here we report a promising memristor employing a plasma-enhanced chemical vapour deposition (PECVD) bilayer of amorphous SiC/Si as device layer and Cu as an active electrode. Its endurance exceeds one billion cycles with an ON/OFF ratio of ca. two orders of magnitude. Resistance drift is observed in the first 200 million cycles, after which the devices settle with a coefficient of variation of ca. 10% for both the low and high resistance states. Ohmic conduction in the low resistance state is attributed to the formation of Cu conductive filaments inside the bilayer structure, where the nanoscale grain boundaries in the Si layer provide the pre-defined pathway for Cu ion migration. Rupture of the conductive filament leads to current conduction dominated by reverse bias Schottky emission. Multistate switching is achieved by precisely controlling the pulse conditions for potential neuromorphic computing applications. The PECVD deposition method employed here has been frequently used to deposit typical BEOL SiOC low-k interlayer dielectrics. This makes it a unique memristor system with great potential for integration.

Optimizing PECVD a-SiC:H Films for Neural Interface Passivation

This work aims to optimize Plasma-Enhanced Chemical Vapour Deposition (PECVD) amorphous hydrogenated silicon carbide (a-SiC:H) as a conformal passivation layer for invasive microelectrode array (MEA) neural interface applications. By carefully tuning the PECVD deposition parameters, the composition, structure, electrical, and mechanical properties of the films can be optimized for high resistivity, low stress, and great resistance to chemical attack. This optimization will eventually allow a-SiC:H to be used as an ideal insulation, passivation and protection layer for thin and biocompatible all-SiC neural interfaces.

Characterization of structural and mechanical properties of DLC films deposited on the surface of minute-scale 3D objects: Comparison of PECVD and FCVA deposition technique

Diamond-like carbon (DLC) films have received considerable attention owing to its excellent properties such as high hardness, low friction coefficient, high wear resistance, and chemical inertness. Because DLC film is considered an effective coating to improve the surface properties of materials, these films are used in various applications such as parts for automobile engines, hard disk surfaces, cutting tools and dies, and so on. The structure of the DLC film consists of a mixture of sp2- and sp3-bonded carbon atoms. Among them, the tetrahedral amorphous carbon (ta-C) film is known to be the hardest film owing to its diamond-like structure composed mainly of sp3-bonded carbon atoms. The most common deposition method for synthesizing ta-C is the filtered cathodic vacuum arc (FCVA) method. This method can remove the droplets that are non-ionic neutral species, and a high-quality film can be synthesized. However, the mechanical parts that require ta-C coating have a three-dimensional (3-D) shape, and it is difficult to coat the ta-C film on their entire surface conformity by the FCVA process. In this study, we deposited ta-C on three-dimensional parts by the FCVA method and evaluated the microstructure and surface morphology of the film in comparison with the plasma enhanced chemical vapor deposition (PECVD) method. Films were successfully coated over the entire surface of both millimeter- and nanometer-sized trench patterns. The film properties were investigated by Raman spectroscopy, SEM, nanoindentation tester and transmission electron microscopy.

High-Translucency Zirconia Following Chemical Vapor Deposition with SiH4: Evidence of Surface Modifications and Improved Bonding.

To evaluate the effect of plasma-enhanced chemical vapor deposition (PECVD) with silicon hydride (SiH4) at different times on HT-zirconia surface characteristics and bonding of composite cement before and after thermocycling. Blocks of HT zirconia were obtained, polished, sintered and divided into five groups, according to PECVD time (n = 31): Zr-30 (30 s), Zr-60 (60 s), Zr-120 (120 s) and Zr-300 (300 s). The control group (Zr-0) did not receive PECVD. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), energy dispersive spectroscopy (EDS) in conjunction with field-emission scanning electron microscopy (FE-SEM), x-ray photoelectron spectroscopy (XPS), goniometry, and profilometry tests were used for chemical and topographic characterization. Monobond N silane (Ivoclar Vivadent) was applied to the surface, and a cylinder of composite cement (Variolink N) was made (3 x 3 mm). Half of the specimens of each group were stored for 24 h or subjected to thermocycling (6 x 103 cycles). A shear bond strength (SBS) test was performed. Results were subjected to one-way ANOVA and Tukey's tests (α = 0.05). For experimental groups, XPS showed that formation of Si-O bonds contributed to increased surface free energy (SFE). FE-SEM and EDS showed that the longer the deposition time, the greater the amount of silicon on the surface. Zr-60 and Zr-300 presented higher and lower surface roughnesses, respectively. The silicon penetrated the microstructure, causing higher stress concentrations. The bond strength to composite cement was improved after all PECVD deposition times. The PECVD technique with SiH4, associated with chemical treatment with primer based on silane methacrylate, is a solely chemical surface treatment capable of maintaining bonding between composite cement and HT zirconia.

Optical, structural and composition properties of silicon nitride films deposited by reactive radio-frequency sputtering, low pressure and plasma-enhanced chemical vapor deposition

We present a comparative study of optical properties of silicon nitride thin films deposited by reactive radio-frequency (R-RF) sputtering, low pressure chemical vapor deposition (LPCVD) and plasma-enhanced chemical vapor deposition (PECVD). For LPCVD process, two different proportions of mixed gases were used (LPCVD (A) and LPCVD (B) processes) and PECVD deposition were conducted in three regimes: low frequency (LF), mixed frequency and high frequency. Dielectric functions were extracted from ellipsometric measurements for the wavelength range from ultraviolet to near-infrared wavelengths, spanning from 210 nm to 1690 nm. To understand how different deposition parameters affect the optical properties of thin films, additional structures and composite analysis was done by using X-ray photoelectron spectroscopy, grazing incidence X-ray diffraction, X-ray reflectometry, atomic force microscopy, reflection electron energy loss spectroscopy, Fourier-transform infrared spectroscopy and stress measurements. The series of analysis show that the influence of deposition method on optical properties is significant especially for in the range of 200 nm–400 nm. For these UV wavelengths, LPCVD (A)-deposited films give a transparency window at the shortest wavelength up to 275 nm, while R-RF-sputtering and PECVD (LF) lead to transparency windows starting up to 320 nm wavelengths. Hence, appropriate techniques and recipes should be selected to account for various peculiarities in optical and structural properties of silicon nitride films towards their potential applications in photonic and nanostructured systems.

Emitter formation with boron diffusion from PECVD deposited boron-doped silicon oxide for high-efficiency TOPCon solar cells

We present a systematic study of emitter formation with dopant diffusion from boron (B)-doped hydrogenated silicon oxide (a-SiOx:H) deposited on textured n-type monocrystalline silicon (n-c-Si) wafers using a 13.56 MHz plasma-enhanced chemical vapor deposition (PECVD) system. The B atoms in the a-SiOx:H are activated and diffused into the n-c-Si wafer during a high-temperature annealing to form a p/n junction for solar cell application. Afterward, the B-doped SiOx layer is removed by hydrofluoric acid selective etching to obtain a clean surface for the deposition of AlOx passivation and SiNx antireflection layers. With the optimization of the PECVD deposition and the following annealing/etching processes, the B diffused region with a sheet resistance of 60–100 Ω/sq and a junction depth of 1.2–1.5 μm is obtained. A champion implied open-circuit voltage (iVoc) of 705 mV and a single-side saturated recombination current density (J0,s) of 17.6 fA/cm2 are obtained from a double-sided B diffused sample after the passivation with an atomic-layer-deposition (ALD) AlOx. In addition, the contact resistivity (ρc) at the metal/emitter interface is lower than 5 mΩcm2, where the metal contact is a Ti/Pd/Ag tri-layer structure. All of the material properties meet the requirements of high-efficiency solar cell. With the optimized emitter in the front, we made a SiOx and heavily phosphorus-doped polycrystalline silicon carbide (n-poly-SiCx) stack on the rear surface to form tunnel oxide passivated contact (TOPCon) solar cells. The results show that the iVoc of semi-finished TOPCon solar cell before metallization is more than 725 mV. Finally, a TOPCon solar cell with an efficiency of 24.24% is obtained, which is comparable with the TOPCon solar cells with the industrial thermally diffused emitter.

A COMPREHENSIVE REVIEW ON THIN FILM DEPOSITIONS ON PECVD REACTORS

The deposition of thin films by Plasma Enhanced Chemical Vapor Deposition (PECVD) method is a critical process in the fabrication of MEMS or semiconductor devices. The current paper presents an comprehensive overview of PECVD process. After a short description of the PECVD reactors main layers and their application such as silicon oxide, TEOS, silicon nitride, silicon oxynitride, silicon carbide, amorphous silicon, diamond like carbon are presented. The influence of the process parameters such as: chamber pressure, substrate temperature, mass flow rate, RF Power and RF Power mode on deposition rate, film thickness uniformity, refractive index uniformity and film stress were analysed. The main challenge of thin films PECVD deposition for Microelectromechanical Systems (MEMS)and semiconductor devices is to optimize the deposition parameters for high deposition rate with low film stress which and if is possible at low deposition temperature.

Influence of PECVD Deposition Power and Pressure on Phosphorus-Doped Polysilicon Passivating Contacts

Passivating contacts for silicon solar cells can be fabricated by depositing a layer of intrinsic amorphous silicon (a-Si) by the plasma-enhanced chemical vapor deposition (PECVD) onto an oxidized silicon wafer, followed by a thermal POCl3 diffusion process. This article describes the influence of the main PECVD parameters, power and pressure, on the electrical performance of such phosphorus-doped polysilicon (doped-Si/SiOx) passivating contacts. We characterize their properties in terms of the passivation quality and carrier selectivity for different PECVD powers and pressures. The deposition power settings from 350 to 800 W are tried, the highest iV oc value of 721 mV is achieved at a power of 500 W. The higher deposition powers (≥650 W) lead to blistering issues and possible interface damage, while a lower deposition power (350 W) leads to incomplete decomposition of the precursor gas, resulting in a lower passivation quality. Meanwhile, the power has a marginal impact on the contact resistivity. On the other hand, the deposition pressure has only a slight impact on the passivation quality, while significant changes are observed on the contact resistivity. A lower pressure (0.1 mbar) leads to a higher contact resistivity, while the low and consistent contact resistivity values of 5.8 mΩ·cm2 are obtained at the pressures above 0.2 mbar.

Evolutionary PERC+ solar cell efficiency projection towards 24% evaluating shadow-mask-deposited poly-Si fingers below the Ag front contact as next improvement step

Monofacial PERC and bifacial PERC + solar cells have become the mainstream solar cell technology exhibiting conversion efficiencies around 22.5% in mass production. We determine a specific saturation current density J0,Ag = 1400 fA/cm2 of the screen-printed Ag front contact. When weighted with the contact area fraction of 3.0% the Ag metal contacts contribute 42 fA/cm2 to the total J0,total = 130 fA/cm2 thereby being a main limitation of the Voc. We investigate carrier selective poly-Si on oxide (POLO) fingers below the screen-printed Ag contacts of PERC + solar cells in order to minimize contact recombination. We name this solar cell PERC + POLO. Numerical simulations reveal that PERC + POLO cells exhibit an efficiency potential up to 24.1% which is 0.3%abs. higher compared to PERC + solar cells. In order to enable low-cost manufacturing of poly-Si fingers, we investigate for the first time the deposition of suitable a-Si fingers by plasma-enhanced chemical vapour deposition (PECVD) through a shadow mask in a vacuum chamber. We demonstrate a-Si fingers as narrow as 70 μm and as high as 250 nm. The parasitic deposition below the mask increases the a-Si finger width by less than 30 μm compared to the mask opening width. First test wafers demonstrate an implied Voc up to 716 mV of PECVD a-Si layers which are crystalized and doped in a subsequent POCl3 diffusion. Applying this process sequence, PERC + POLO cells could be manufactured with the established industrial PERC + process only adding the PECVD deposition of a-Si fingers through a shadow mask.

All-dry patterning method to fabricate hydrophilic/hydrophobic surface for fog harvesting

Inspired by natural creatures that live in the arid climate, fog harvesting can be an efficient approach to overcome freshwater scarcity. Fog harvesting ability of the creatures is mainly based on wettability differences of their surfaces. In this study, inspired by creatures that have hydrophilic regions surrounded by hydrophobic areas, a novel all-dry patterning method was applied to fabricate hydrophilic/hydrophobic patterned surfaces for fog harvesting. For this purpose, patterned surfaces were produced using plasma-enhanced chemical vapor deposition (PECVD) method with the help of a commercial magnet and iron powders. The idea behind the use of the magnetic field during PECVD deposition is to hold light iron particles on the substrate under the vacuum environment for masking substrate surface. For the first time, the magnetic field was used to fabricate patterned surfaces in vapor-phase polymerization. Ordinary glass slides were successfully transformed into hydrophilic/hydrophobic patterned glasses. The obtained results showed that the combination of hydrophobic and hydrophilic regions improved the fog harvesting performance.

Influence of PECVD deposition temperature on phosphorus doped poly-silicon passivating contacts

This paper describes the influence of plasma enhanced chemical vapor deposition (PECVD) deposition temperature on heavily doped silicon based (doped-Si/SiOx) passivating contacts for silicon solar cells. The doped-Si films are obtained by PECVD intrinsic amorphous silicon (a-Si) and a subsequent thermal POCl3 diffusion process. By changing the deposition temperature of PECVD, a-Si films with different degrees of crystallinity and density can be obtained. These differences between the a-Si films result in different properties of the passivating contacts in terms of passivation quality and carrier selectivity. By exploring a range of PECVD deposition temperatures from 250 °C to 470 °C, the best passivation quality is obtained at a temperature of 420 °C. On the other hand, the contact resistivity decreases with increasing deposition temperature. After studying the a-Si properties and the resulting passivating contact properties, we obtain optimal passivating contacts with a high implied open-circuit voltage (iVoc) of 742 mV and a low contact resistivity ρc of 6.4 mΩ∙cm2.

Silicon Nitride Deposition: Impact on Lifetime and Light-Induced Degradation at Elevated Temperature in Multicrystalline Silicon

Light and elevated temperature induced degradation (LeTID) in multicrystalline (mc) silicon (Si) is known to be sensitive to the silicon nitride (SiN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> :H) deposition and the firing, but the reason remains unknown. Three plasma-enhanced chemical vapor deposition (PECVD) tools are used to deposit five different layers, causing significant differences in the initial lifetimes before and after firing. The impact of the different depositions can be effectively compared by replacing the SiN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> :H with well-passivating room-temperature iodine ethanol passivation (IE). The IE passivation reveals that the firing of SiN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> :H and subsequent bulk hydrogenation leads to a lifetime increase only in the gettered samples. Although the PECVD temperature load affects the bulk lifetime, it does not cause LeTID without SiN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> :H deposition. LeTID is only detected in samples fired with SiN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> :H, but once the LeTID precursors have been activated, the PECVD layer can be etched and the wafer thinned down without affecting LeTID formation. No link is found between the LeTID defect density and the bulk-hydrogenated lifetime. Instead the LeTID defect density appears to decrease with decreasing PECVD deposition time and temperature.

Plasma-Chemistry of Arsenic Selenide Films: Relationship Between Film Properties and Plasma Power

High quality amorphous arsenic selenide chalcogenide films of different structure and stoichiometry were synthesized via plasma-enhanced chemical vapor deposition (PECVD). The low-temperature non-equilibrium RF (13.56 MHz) argon inductively-coupled plasma at low pressure (0.1 Torr) was implemented for the process. Commercial high-pure elemental arsenic and selenium were utilized as the starting materials. The chemical content and the structure of the samples were altered via change of parameters of the plasma process. The in situ optical emission spectroscopy of the chemically active plasma was employed to pinpoint the ways of initiation of plasma-chemical interactions between precursors. The obtained characteristics of the arsenic selenide PECVD films have been compared with ones for CVD. The behavior of impurities of the carbon nature in the processes of PECVD and CVD deposition was also studied.

Inline PECVD Deposition of Poly‐Si‐Based Tunnel Oxide Passivating Contacts

In this publication, the deposition of a‐Si(n) layers using an industrially relevant inline plasma‐enhanced chemical vapor deposition (PECVD) tool for the successful realization of passivating contacts is reported. Dynamic inline deposition has the potential to increase production throughput and yield compared to the conventional cluster‐like PECVD tools which is the current standard for deposition of a‐Si:H layers. Besides structural investigations concerning absorbance and band gap energy of these layers, the dependence of layer thickness and PH3 gas phase doping on implied open circuit voltage iVOC, sheet resistance, and the corresponding diffusion profile is investigated. A significant influence of PH3 gas phase doping is demonstrated whereas no significant dependence of the layer thickness is elaborated. Excellent values of iVOC = 740 mV and iFF = 85% on planar and iVOC = 720 mV and iFF = 84% on textured surfaces can be reached implementing the developed n‐doped layers in the tunnel oxide passivating contact (TOPCon) structure.

AlGaN/GaN MOS-HEMT Device Fabricated Using a High Quality PECVD Passivation Process

In this letter, an AlGaN/GaN MOS-HEMT was demonstrated using a 5-nm-thick SiOx dielectric layer deposited by plasma enhanced chemical vapor deposition (PECVD) as a gate insulator. The fabricated device exhibits a maximum ${I}_{{\text {DS}}}$ current of 570 mA/mm at ${V}_{{\text {GS}}} =+ {3}$ V, an ON-state resistance ( ${R}_{\mathrm {biosc{on}}}$ ) of $7.3~\Omega \cdot $ mm, a maximum transconductance peak of 180 mS/mm, and a gate leakage current below 1 nA/mm at a gate voltage of +/−3 V. Moreover, a very low pinchoff voltage ( ${V}_{p})$ shift was observed during the ${I}_{{\text {DS}}}$ – ${V}_{\text {GS}}$ hysteresis measurements giving an estimated interface state density ( ${D}_{\text {it}})$ as low as $3.9\times 10^{ {11}}$ cm $^{-2}$ eV $^{-1}$ . These results demonstrate the high quality of the SiO x /AlGaN interface and the efficiency of the passivation process. To the best of our knowledge, this is the lowest reported ${D}_{\text {it}}$ on an AlGaN/GaN MOS-HEMT device using a PECVD deposition technique.

Fabrication of SiNx Thin Film of Micro Dielectric Barrier Discharge Reactor for Maskless Nanoscale Etching.

The prevention of glow-to-arc transition exhibited by micro dielectric barrier discharge (MDBD), as well as its long lifetime, has generated much excitement across a variety of applications. Silicon nitride (SiNx) is often used as a dielectric barrier layer in DBD due to its excellent chemical inertness and high electrical permittivity. However, during fabrication of the MDBD devices with multilayer films for maskless nano etching, the residual stress-induced deformation may bring cracks or wrinkles of the devices after depositing SiNx by plasma enhanced chemical vapor deposition (PECVD). Considering that the residual stress of SiNx can be tailored from compressive stress to tensile stress under different PECVD deposition parameters, in order to minimize the stress-induced deformation and avoid cracks or wrinkles of the MDBD device, we experimentally measured stress in each thin film of a MDBD device, then used numerical simulation to analyze and obtain the minimum deformation of multilayer films when the intrinsic stress of SiNx is −200 MPa compressive stress. The stress of SiNx can be tailored to the desired value by tuning the deposition parameters of the SiNx film, such as the silane (SiH4)–ammonia (NH3) flow ratio, radio frequency (RF) power, chamber pressure, and deposition temperature. Finally, we used the optimum PECVD process parameters to successfully fabricate a MDBD device with good quality.

Chemical sputtering by H2+ and H3+ ions during silicon deposition

We investigated chemical sputtering of silicon films by Hy+ ions (with y being 2 and 3) in an asymmetric VHF Plasma Enhanced Chemical Vapor Deposition (PECVD) discharge in detail. In experiments with discharges created with pure H2 inlet flows, we observed that more Si was etched from the powered than from the grounded electrode, and this resulted in a net deposition on the grounded electrode. With experimental input data from a power density series of discharges with pure H2 inlet flows, we were able to model this process with a chemical sputtering mechanism. The obtained chemical sputtering yields were (0.3–0.4) ± 0.1 Si atom per bombarding Hy+ ion at the grounded electrode and at the powered electrode the yield ranged from (0.4 to 0.65) ± 0.1. Subsequently, we investigated the role of chemical sputtering during PECVD deposition with a series of silane fractions SF (SF(%) = [SiH4]/[H2]*100) ranging from SF = 0% to 20%. We experimentally observed that the SiHy+ flux is not proportional to SF but decreasing from SF = 3.4% to 20%. This counterintuitive SiHy+ flux trend was partly explained by an increasing chemical sputtering rate with decreasing SF and partly by the reaction between H3+ and SiH4 that forms SiH3+.

21.0%-efficient screen-printed n-PERT back-junction silicon solar cell with plasma-deposited boron diffusion source

The manufacturing process of Passivated Emitter and Rear Totally diffused (PERT) solar cells on n-type crystalline silicon is significantly simplified by applying multifunctional layer stacks acting as diffusion source, etching and diffusion barrier. We apply boron silicate glasses (BSG) capped with silicon nitride (SiNz) layers that are deposited by means of plasma enhanced chemical vapor deposition (PECVD). Optimum PECVD deposition parameters for the BSG layer such as the gas flow ratio of the precursor gases silane and diborane SiH4/B2H6=8% and the layer thickness of 40nm result in a boron diffusion with saturation current density J0,B below 10fA/cm2 applying an AlOx/SiNy passivation and firing. The PECVD BSG diffusion source is integrated into the n-type PERT back junction (BJ) solar cell process with screen-printed front and rear contacts. The only high temperature step is a POCl3 co-diffusion for the formation of the boron emitter from the PECVD BSG layer and for the formation of the phosphorus-doped front surface field (FSF). An independently confirmed energy conversion efficiency of 21.0% is achieved for a 156×156mm2 large n-PERT BJ cell with this simplified process flow. This is the highest efficiency reported for a large-area co-diffused n-type PERT BJ solar cell using a PECVD BSG as diffusion source. For comparison, reference n-type PERT BJ cells with separate POCl3 and BBr3 diffusions reach an efficiency of 21.2% in our lab. A synergistic efficiency gain analysis (SEGA) for the co-diffused n-PERT BJ cell shows that the main possible efficiency gain of 1.1%abs. originates from recombination in the phosphorus-diffused front surface field while the PECVD BSG boron-doped emitter accounts for only 0.1%abs. efficiency gain. We evaluate the use of the PECVD BSG/SiNz stack as a rear side passivation as a replacement of the AlOx/SiNy stack in order to further simplify the process flow. We obtain J0,B values of 40fA/cm2, an implied open-circuit voltage of 682mV and a simulated n-PERT BJ cell efficiency of 21.1%.

PECVD polymerised coatings on thermo-sensitive plastic support

With this paper we describe several alternative approaches aimed at polymer-on- polymer coatings, produced by Plasma Enhanced Chemical Vapour Deposition (PECVD) technique. In our case three types of input compounds were applied for varied “cold plasma” PECVD deposition of nano-thick functional layers: namely hexamethyldisiloxane (HMDSO), pentane and toluene onto plastic substrates. The output characterisations through SEM imaging, ATR-FTIR, EDX, AFM and contact angle measurements, proved the methods’ feasibility and properties of the plasma-polymerised coatings.