Thin Silicon Layer Research Articles

Investigating the Efficacy of Anatomical Silicone Models Developed from a 3D Printed Mold for Perineal Repair Suturing Simulation.

There is a scarcity of affordable, validated, standardized and anatomically correct silicone perineum models for the rehearsal of postpartum laceration repair. The purpose of this technical report is to describe and validate evidence for a silicone, perineal repair model created from a 3D printed mold for medical resident training and clinical skills maintenance.A pre-existing model from an open-source royalty-free website was purchased and converted using Fusion360TM (Autodesk Inc., San Rafael, CA, USA) into a stereolithography (.stl) file and altered to produce a negative mold. Using a spatula, a fine silicone layer was first applied inside the mold, followed by a small piece of flesh-colored mesh netting material within the perineal surface area, fitting the width of the mold. The mesh was pressed into the thin layer of silicone, which was meant to provide anatomical structure to prevent the sutures from tearing through the silicone. The remainder of the silicone mix was then poured into the mold, which required three hours to fully set before being removed from the mold. Twelve silicone models were produced and used during a one-hour workshop at the Rural and Remote Conference by 16 obstetrics and gynecology residents and practicing rural physicians, and four facilitators. At the end of the workshop, the participants were provided with a qualitative survey and asked to rate the perceived realism and educational effectiveness of the silicone perineum model as compared to pre-existing simulation models that they have used previously. The overall workshop participant feedback was positive, noting that the models provided more realistic visualization for the suturing simulation of first- and second-degree perineal injuries.The silicone models were considered to be useful in simulation training when attempting first- and second-degreeperineum suturing techniques within a confined space. The overall feedback was positive, noting that they provided more realistic visualization experience compared to pre-existing simulation models, such as beef tongues and synthetic sponges. The feedback from the participants and facilitators included thoughts about how to add additional mesh to the silicone model so the subcutaneous and vaginal plane sutures would hold, as well as increase the size of the vaginal canal size to more accurately represent a postpartum repair. There were also suggestions to alter the colour of the model to be flesh-toned as opposed to pink, to more accurately simulate human tissue.Silicone perineum models, created from a 3D printed mold, are an economical training tool as compared to commercially available, cost prohibitive models. They also provide anatomically accurate simulation training opportunities for residents to learn and maintain clinical skills in perineal repair, as compared to beef tongues and synthetic sponges, which have previously been used in obstetrics and gynecology simulation-based medical education.

New methods to identify low energy 3He with Silicon-based detectors

Methods to discriminate low energy mass-3 particles using Silicon detectors are reviewed. The time-of-flight technique based on analog electronics and measuring time between a reference signal and the charge signal from the Silicon detector does not allow to discriminate 3He from 3H. One method consists in adding a thin layer of Silicon (typically of 20μm) to recover the standard discrimination by ΔE-E identification matrix. Strong inhomogeneities in thickness are observed for these thin detectors. Difficulties in handling such detectors have led to investigate numerical approaches using reverse-mounted neutron transmutation doped Silicon detectors. First, the pulse shape analysis (PSA) technique has been investigated on the current and charge signals. PSA enables the discrimination of tritons and 3He and also 3He and 4He with good figures of merit. Secondly, the time of flight between two digitized signals (a reference signal from the beam pulse and the current or the charge signal) is presented. Both numerical techniques give promising results for the identification of light particles with Silicon detectors.

Formula omitted] thin Low Gain Avalanche Detectors (LGAD) for timing applications

LGAD detectors on 300μm thick high resistivity p-type substrates were proposed for the first time by IMB-CNM-CSIC. They are customized Avalanche Photodiodes (APD) to obtain a high electric field region confined close to the reversed junction. Therefore, only electrons generated by an incident particle passing through the detector and drifting to the n+ contact, start the impact ionization process. Thus, the collected charge is multiplied. The basic difference between APDs and LGADs is the gain. LGADs have a moderate gain in order to avoid the inherent problems due to high multiplication: cross talk and high noise. In that way, the detector signal can be kept high without increasing the noise.These devices have been successfully fabricated and extensively characterized, before and after irradiation. Unfortunately, neutron and proton radiation cause the degradation of the gain and the creation of bulk traps, degrading the timing resolution. One way to reduce the radiation induced degradation is to minimize the substrate thickness, thus improving the timing resolution of LGAD detectors.Two technology approaches have been contemplated: the use of SOI (Silicon on insulator) substrates and Silicon to Silicon bonding substrates, both with a very thin active silicon layer of 50μm. As a consequence, drifting distances of generated electrons and holes are significantly reduced, resulting in a decrease in the number of electrons and holes trapped by radiation induced bulk defects.A new family of thin detectors, produced in 2×2 arrays prototypes, for the ATLAS experiment High Granularity Timing Detector (HGTD) is proposed. These detectors are suitable for timing applications with time resolution in the range of 30 ps at 20 °C. Optimization of the LGAD structures for the HGTD experiment and the detector experimental performances are presented and discussed.

Chiral visible light metasurface patterned in monocrystalline silicon by focused ion beam

High refractive index makes silicon the optimal platform for dielectric metasurfaces capable of versatile control of light. Among various silicon modifications, its monocrystalline form has the weakest visible light absorption but requires a careful choice of the fabrication technique to avoid damage, contamination or amorphization. Presently prevailing chemical etching can shape thin silicon layers into two-dimensional patterns consisting of strips and posts with vertical walls and equal height. Here, the possibility to create silicon nanostructure of truly tree-dimensional shape by means of the focused ion beam lithography is explored, and a 300 nm thin film of monocrystalline epitaxial silicon on sapphire is patterned with a chiral nanoscale relief. It is demonstrated that exposing silicon to the ion beam causes a substantial drop of the visible transparency, which, however, is completely restored by annealing with oxidation of the damaged surface layer. As a result, the fabricated chiral metasurface combines high (50–80%) transmittance with the circular dichroism of up to 0.5 and the optical activity of up to 20° in the visible range. Being also remarkably durable, it possesses crystal-grade hardness, heat resistance up to 1000 °C and the inertness of glass.

Novel bionanocellulose based membrane protected with covalently bounded thin silicone layer as promising wound dressing material

Modification of membrane surface fabricated from bionanocellulose (BNC) carboxymethylcellulose (CMC) blend (BNC-CMC) with covalently bounded silicone layer was carried out in view of developing the novel, moist wound dressing material. The procedure was initiated with the reaction of aminopropyltriethoxysilane (APS) with carboxymethyl groups of CMC resulting with amide bound formation. The thickness of the silicone layer was further increased in the base-catalyzed polycondensation of silicone precursors: vinyltriethoxysilane (VES) or allyltrimethoxysilane (ATMS) initiated by N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDC). Surface modification was confirmed using various physicochemical methods such as FTIR, SEM, XPS and contact angle measurements. Swelling and drying tests confirmed that silicone-modified materials have considerable better water storage properties than the pristine BNC-CMC nanocomposite. The fabricated silicone modified BNC-CMC membranes are promising materials for wound dressing ensuring improved hydrobalance as the protective layer slows the evaporation of water.

Aggrandize efficiency of ultra-thin silicon solar cell via topical clustering of silver nanoparticles

A highly efficient photovoltaic nanocomposite device is demonstrated by fabrication of structural clusters of silver nanoparticles (Ag NPs) on silicon solar cells via a boil deposition method. The efficiency of silicon solar cell was augmented by coating Ag NPs ultra-thin-film deposition on silicon solar cell. Chemically synthesized silver NP’s, their consumption on a silicon thin layer and the operation of photovoltaic nanocomposite device were characterized by using several electron probe microscopic pectroscopic and spectrometric techniques viz. x-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HR-TEM), Photoluminescence, UV–visible absorption, dielectric, current vs. voltage (I∼V) and capacitance vs. voltage (C∼V) characteristics. Poly-dispersed nature of ‘Ag’ nanoparticles established the anisotropy of these NPs when coated on silicon solar cells. Their efficiency enhancement was confirmed from HR-TEM image via time-domain finite-difference technique to deliberate the particle distribution effect on an ultra-thin film of silicon solar cell, indicating the sufficient enrichment in the efficiency of solar cell. Furthermore, the current work explores the developement of novel glass frits for utilization in next generation of high efficiency smart solar cells.

(Invited) The Crucial Role of Nano-Sized Porosity in the Lithiation and Stability of Methylated Amorphous Si Electrodes for Li-Ion Batteries

Silicon electrodes are attracting for lithium-ion batteries but their use is impeded by their poor mechanical stability upon operation (huge volume variation takes place upon electrochemical Li insertion in and extraction from the material) and a poorly-controlled growth of surface layers resulting from the electrolyte decomposition products (the so-called solid-electrolyte interphase, SEI). A thin layer of methylated amorphous silicon a-Si(1-x)(CH3) x :H has a much better resistance to electrochemical lithiation/delithiation cycles than amorphous silicon a-Si:H [1]. Methylated amorphous silicon is a carbon-silicon alloy, deposited using PECVD, in which carbon is incorporated in the bulk material under the form of methyl groups CH3 only. We have studied the lithiation processes in the material for various methyl contents x ranging from 0 (a-Si:H) to 0.12. The lithiation process has been investigated using operando infrared spectroscopy in geometry of attenuated total reflection (ATR) where the active thin layer (30 nm) is directly deposited at the surface of the ATR prism. For all the investigated values of the methyl content x in the material, it was observed that the first lithiation proceeds according to a two-phase mechanism [2]: a (highl²y) lithiated phase with a well-defined Li content z (Li z Si phase) progressively invades the active-material film; if lithiation is performed in galvanostatic mode, this regime corresponds to the observation of a potential plateau. When lithiation is pursued beyond the potential plateau, a single-phase behavior is observed: the Li concentration in the active film becomes uniform and increases as long as the lithiation current is maintained. Delithiation and subsequent lithiation/delithiation cycles proceed homogeneously according to this single-phase behavior. When the electrode is thicker (200 nm), extensive electrochemical cycling results in the cracking of the film. The appearance of the crack network can be followed by operando optical microscopy. When the active film is deposited on a reflecting substrate such as stainless steel, the lithiation can also be followed using the same technique by monitoring of interference colors, since the lithiation results in a thickening of the film and in a change of its refractive index. The quantitative analysis of the two-phase regime of the first lithiation shows that the Li content z in the invading phase depends in a non-trivial way upon the methyl content x of the material: z first decreases upon increasing x, then for values of x larger than 0.05, z increases when increasing x. This behavior can be rationalized in the framework of a model describing the first lithiation of a-Si(1-x)(CH3) x :H. Noteworthy, the regime in which z increases upon increasing x can be ascribed to the existence of a methyl-induced porosity of the material at the nanometric scale. Moreover, the careful analysis of color patterns during lithiation demonstrates that the locations at which the lithiation occurs is not homogeneous at the very beginning of the second cycle: color change can be identified at the locations where future cracks will appear (at the end of the second delithiation of the electrode or later). Possible implications regarding the optimization of the material for its use as electrodes in Li-ion batteries will be discussed.

(Invited) SOI Wafer Technology for Advanced Mos Applications

Emerging microelectronic applications such as Internet-Of-Things (IOT) or mixed signal processing utilize fully depleted MOSFETs built on SOI wafers. Advanced FD devices such as planar MOSFETs with back gate biasing require wafers with thin Si top layer as well as ultra thin BOX layer. To sustain good electrostatic control of the channel and to keep back-gate voltages reasonably low, top Si layer thickness has to be in the 5-10 nm range and BOX thickness needs to be less than 20 nm. The SmartCutTM process is the only technology that allows transferring extremely thin layers of silicon on a wide range of handling substrates with industrial quality. As threshold voltage of FD SOI transistor depends on the thickness of Si layer, the thickness has to be controlled within extremely tight tolerance, typically + /- 5A in full range of spatial frequencies spanning from 10 nm till 300 mm [1]. This creates challenge not only for manufacturing technology, but requires development of new thickness metrology. Introduction of differential reflection microscopy (DRM) [2] allows in-line SOI thickness control in wide range of spatial frequencies with unprecedented throughput and precision. The principles and main applications of DRM will be discussed in the presentation. The key process steps with their influence on specific spatial frequencies are identified. One of the main contributors to mid range frequency (in mm range) thickness variation is the interaction of propagating fracture front with acoustic waves emitted by itself. The experimental verification of this mechanism as well as the results of numerical simulations will be presented. Another critical process in SOI technology is reduction of high frequency thickness variations during finishing steps. Possibilities of using pure surface diffusion as well as chemically enhanced high temperature smoothing will be demonstrated. It will be shown that during high temperature annealing in neutral atmosphere Si surface evolution can be described by Mullings-Herring equation with two extra stochastic terms, responsible for conservative and non-conservative noise, while addition of HCl to the annealing atmosphere changes surface behavior to surface relaxation described by the Edwards-Wilkinson model. General linear 4th order surface development model is proposed covering both mechanisms. Material parameters for the model are determined experimentally in the case of HCl(<1%)/H2 etching of silicon. For some advanced applications base wafer of SOI structure can play functional role in the final device, not limited to a mechanical support. One of such examples is RF SOI substrates specifically designed for RF analog applications, such as front end RF modules in smartphones. Introduction of thermally stable layer with high density of carrier traps between BOX layer and high resistivity Si substrate significantly improves high frequency electrical parameters of the devices built on such substrates [3]. Insertion loss, second harmonic generation of coplanar waveguides as well as quality factors of inductors are such main parameters. Empirical model is presented which allows prediction of the results of RF measurements from simple SRP data.

Performance study of optical resonator‐based filter architectures

A comparative study on characteristics and performance of optical ring resonator architectures, i.e. circular, racetrack, and triangular-shaped optical resonators, have been carried out here. Constituent material used for designing these resonators is an silicon on insulator wafer consisting of thin silicon (Si) layer on silica (SiO2) layer carried on a thick Si substrate having group index of 2.379. All the resonators are so designed that all provide equal free spectral range (FSR) of 25.2 THz. All these double-ring architectures have been analysed using delay line signal processing technique in z-domain and Mason's gain formula. FSR expansion has been achieved employing the Vernier principle. Various performance defining parameters have been also investigated.

A new interdigitated back contact silicon solar cell with higher efficiency and lower sensitivity to the heterojunction defect states

A new interdigitated back contact silicon heterojunction (IBC-SHJ) solar cell with two additional buffer layers is investigated. The buffer layers are two thin p-type crystalline silicon (c-Si) layers placed at front and back surface of c-Si/a-Si:H hetero-junction interfaces. Improvement of the overall efficiency and decrease in sensitivity of the output parameters to c-Si/a-Si:H interface defect density through the controlling of carrier concentration by introducing the new structure is achieved. The impact of new buffer layers on the cell performance is studied with numerical modeling. The main output parameters of the IBC-SHJ solar cell including buffer layers are compared with the conventional IBC-SHJ solar cell. It is found that the new IBC-SHJ solar cell has a higher fill factor due to reduced series resistance. With a deeper study on the impact of the buffer layers, it is realized that the field effect passivation has a key role in the improvement of the new cell performance. By modifying the energy band structure through the buffer layers, recombination at the c-Si/a-Si:H heterojunction interfaces is reduced due to the field effect passivation of the c-Si surface, and the efficiency of the solar cell is increased. Optimizing doping concentration and thickness of the buffer layers leads to an increase of 5% in fill factor and an increase of 1.2% in efficiency compared with the conventional similar solar cell.

Surface plasmons in new waveguide structures containing ultra-thin metal and silicon layers

Reflected and transmitted powers due to the interaction of electromagnetic waves with a structure containing thin metal and silicon layer are investigated in more detail. The formulations for the transverse electric wave case are provided. Transfer matrix method is used to find the reflection and the transmission coefficients at each interface. Numerical results are presented to show the effect of the structure parameters, the incidence angle and the wavelength on the reflected, transmitted and loss powers.

Evolution of Phase Transformation in Thin Layers of Amorphous Silicon Under Micro/Indented Loading

The present study aims the presentation of the phase evolution in a thin layer of amorphous silicon intended by loads to localize and to quantify phenomena during the phase transformation. To reach these objectives, Vickers micro/indentation is used applying different values of force on the specimen. In this work three techniques, such as: scanning electron microscope, micro/Raman spectroscopy and x-ray diffraction are used to study the transformation of phases in silicon subjected to different micro/indentation loads. The elaborated experimental work leads to explain obtained results, such as: (1) the correlation between micro/indentation loads and microstructure changes, (2) the behavior of imprint taken from a-Si thin layers of the applied load and (3) the formation of βSi3N4, which depends principally on indented loads. In general, the phase transformation evolution in the thin layer of amorphous silicon was highly established by experimental works.

Honeycomb micro-textures for light trapping in multi-crystalline silicon thin-film solar cells.

The liquid phase crystallization (LPC) of silicon is an emerging technology for fabricating 10 - 20 µm thin multi-crystalline silicon layers on glass. LPC silicon solar cells exhibit similar electronic performance to multi-crystalline wafer-based devices. Due to the reduced absorber thickness, however, effective measures for light trapping have to be taken. We present tailor-made micro-structures for light trapping at the LPC silicon back-side, whereby a nano-imprinted resist layer serves as a three-dimensional etching mask in subsequent reactive ion etching. Contrary to state-of-the-art random pyramid textures produced by wet-chemical etching, this method allows to produce tailor-made textures independent of grain orientation. Differently shaped micro-textures were replicated in LPC silicon. Absorptance and external quantum efficiency of periodic honeycomb patterns and random pyramids were found to be equivalent. Thus, the method enables the potential to further optimize light trapping in LPC silicon solar cells.

Photon counting statistics of superconducting single-photon detectors made of a three-layer WSi film

Superconducting nanowire single-photon detectors (SNSPD) are used in quantum optics when record-breaking time resolution, high speed, and exceptionally low levels of dark counts (false readings) are required. Their detection efficiency is limited, however, by the absorption coefficient of the ultrathin superconducting film for the detected radiation. One possible way of increasing the detector absorption without limiting its broadband response is to make a detector in the form of several vertically stacked layers and connect them in parallel. For the first time we have studied single-photon detection in a multilayer structure consisting of three superconducting layers of amorphous tungsten silicide (WSi) separated by thin layers of amorphous silicon. Two operating modes of the detector are illustrated: an avalanche regime and an arm-trigger regime. A shift in these modes occurs at currents of ∼0.5–0.6 times the critical current of the detector.

Performance study of double SOI image sensors

Double silicon-on-insulator (DSOI) sensors composed of two thin silicon layers and one thick silicon layer have been developed since 2011. The thick substrate consists of high resistivity silicon with p-n junctions while the thin layers are used as SOI-CMOS circuitry and as shielding to reduce the back-gate effect and crosstalk between the sensor and the circuitry. In 2014, a high-resolution integration-type pixel sensor, INTPIX8, was developed based on the DSOI concept. This device is fabricated using a Czochralski p-type (Cz-p) substrate in contrast to a single SOI (SSOI) device having a single thin silicon layer and a Float Zone p-type (FZ-p) substrate. In the present work, X-ray spectra of both DSOI and SSOI sensors were obtained using an Am-241 radiation source at four gain settings. The gain of the DSOI sensor was found to be approximately three times that of the SSOI device because the coupling capacitance is reduced by the DSOI structure. An X-ray imaging demonstration was also performed and high spatial resolution X-ray images were obtained.

Proof of principle of helium-beam radiography using silicon pixel detectors for energy deposition measurement, identification, and tracking of single ions.

Hadron therapy has the capability to provide a high dose conformation to tumor regions. However, it requires an accurate target positioning. Thus, the precise monitoring of the patient's anatomical positioning during treatment is desirable. For this purpose, hadron-beam radiography with protons (pRad) and ions (iRad) could be an attractive tool complementing the conventional imaging technologies. On the pathway to an envisaged clinical application, several challenges have to be addressed. Among them are achieving the desired spatial resolution in the presence of multiple Coulomb scattering (MCS), performing radiographs with a sufficient thickness resolution at clinically applicable dose levels, and the search for combinations of particularly suitable hadrons and detectors. These topics are investigated in this work for a detection system based on silicon pixel detectors. A method of iRad based on energy deposition measurements in thin layers is introduced. It exploits a detection system consisting of three parallel silicon pixel detectors, which also enables particle tracking and identification. Helium ions, which exhibit less pronounced MCS than protons, were chosen as imaging radiation. A PMMA phantom with a mean water-equivalent thickness (WET) of 192mm, containing maximal WET-variations of ±6mm, was imaged with a 173MeV/u helium ion beam at the Heidelberg Ion-Beam Therapy Center. WET-differences in form of 2.3mm×2.3mm steps were aimed to be visualized and resolved in images of the energy deposition measured behind the phantom. The detection system was placed downstream of the imaged object in order to detect single ions leaving it. The combination of the measured information on energy deposition, ion type, and the track behind the phantom was used for the image formation, employing a self-developed data-processing procedure. It was shown that helium-beam radiography is feasible with the reported detection system. The introduced data preprocessing purified the detector signal from detector artifacts and improved the image quality. Additionally, the rejection of hydrogen ions originating from nuclear interactions was shown to increase the contrast-to-noise ratio (CNR) by at least a factor of 2.5. This enabled the resolution of relative thickness differences of 1.2% at a dose level typical for diagnostic x-ray images. The spatial resolution was improved by taking into account the direction of single helium ions leaving the phantom. A spatial resolution (MTF10% ) of at least 1.15pmm-1 for the presented experimental set-up was achieved. A successful feasibility study of helium-beam radiography with the introduced detection system was conducted. The methodology of iRad was based on energy deposition measurements in thin silicon layers. The tracking of single ions and the method of the ion identification was shown to be important for helium-beam radiography in terms of spatial resolution and CNR.

Impact of He and H relative depth distributions on the result of sequential He+ and H+ ion implantation and annealing in silicon

Sequential He++H+ ion implantation, being more effective than the sole implantation of H+ or He+, is used by many to transfer thin layers of silicon onto different substrates. However, due to the poor understanding of the basic mechanisms involved in such a process, the implantation parameters to be used for the efficient delamination of a superficial layer are still subject to debate. In this work, by using various experimental techniques, we have studied the influence of the He and H relative depth-distributions imposed by the ion energies onto the result of the sequential implantation and annealing of the same fluence of He and H ions. Analyzing the characteristics of the blister populations observed after annealing and deducing the composition of the gas they contain from FEM simulations, we show that the trapping efficiency of He atoms in platelets and blisters during annealing depends on the behavior of the vacancies generated by the two implants within the H-rich region before and after annealing. Maximum efficiency of the sequential ion implantation is obtained when the H-rich region is able to trap all implanted He ions, while the vacancies it generated are not available to favor the formation of V-rich complexes after implantation then He-filled nano-bubbles after annealing. A technological option is to implant He+ ions first at such an energy that the damage it generates is located on the deeper side of the H profile.

Prosthetic Reconstruction for a Patient with Partial Hand Amputation

ABSTRACT Introduction Partial hand amputations are one of the most common types of hand amputation. Provision of an aesthetic prosthesis with adequate performance can reduce negative social and psychological impacts of hand amputation. The aim of this study was to describe the fabrication of a silicone prosthesis for a patient with partial hand amputation. Materials and Methods Alginate impression was taken from the residual limb and donor hand. The thumb of the patient on the affected side was covered with a thin layer of silicone so as to not prevent the natural movements of the fingers. A thin layer of wax sculpted on the residual limb plaster mold of the thumb. Four metal wires were put on the residual limb plaster mold. These metal wires are temporary and, after the curing of silicone, are removed from within the final prosthesis to create a suction suspension and lightweight prosthesis. Result In this study, the prosthesis was designed and built for a 30-year-old woman who worked in a toy factory and had four fingers of her left hand amputated. Conclusion The patient was satisfied with the prosthesis in terms of appearance, weight, and color. The thumb function was not limited by the prosthesis. The patient could easily use her thumb while wearing the prosthesis.

Visualization of Isofrequency Contours of Strongly Localized Waveguide Modes in Planar Dielectric Structures

An experimental method has been proposed to study the dispersion properties of optical surface and waveguide modes in planar structures. An experimental setup involves a microscope with a high numerical aperture objective and a hemispherical solid immersion lens made of zinc selenide in contact with the sample surface. The reflection from the sample is detected in the back focal plane of the system. Such a configuration makes it possible to study strongly localized states with an effective refractive index up to 2.25 in the visible and near infrared spectral ranges. For a thin silicon layer deposited on a glass substrate, the possibility of visualization of isofrequency contrours with polarization resolution and the reconstruction of dispersion of waveguide modes depending on the direction of their propagation has been demonstrated.

Impact of Dielectric Layers on Liquid-Phase Crystallized Silicon Solar Cells

Liquid-phase crystallization (LPC) of thin silicon layers on glass substrates is a technique to fabricate solar cells with low energy and material consumption and open-circuit voltages comparable to multicrystalline silicon wafer cells. We studied the impact of different passivation layers deposited with plasma-enhanced chemical vapor deposition (PECVD) on the cell quality. Silicon nitride (SiNx) and ultrathin silicon oxide (SiO x ) layers with varying thicknesses were used. In addition, we plasma-treated the SiN x surface to form a thin silicon oxynitride (SiO x N y ) passivation layer. Plasma oxidation is an attractive alternative to PECVD, since thicknesses of ultrathin layers can be controlled easier as compared with PECVD. We found that the cell performance is influenced by the passivation layer. Particularly, cells on the 9 nm PECVD SiO x passivation layer are worse than cells on the 11 nm SiO x N y layer. We modeled cell parameters employing ASPIN3 to estimate effective diffusion lengths. Using transmission electron microscopy as well as electron energy loss spectroscopy, we studied the effect of the plasma treatment on the morphology and elemental distribution at the interface between passivation layer and LPC-Si absorber. Our best interdigitated back contacted solar cell with an efficiency >14% is based on the SiO x N y layer.