Time-of-flight Elastic Recoil Detection Analysis Research Articles

Li concentration change around Cu/LiPON interface measured by TOF-ERDA

AbstractLithium metal is a promising anode material for the development of advanced all-solid-state batteries (ASSBs) with high energy density. Among the various solid electrolytes, lithium phosphorus oxynitride glass electrolyte (LiPON) is notable for facilitating stable Li plating-stripping reactions in ASSBs employing Li metal. The aim of this study is to examine the Li/LiPON interface, with a specific emphasis on the reductive decomposition of LiPON near this interface. We employed time-of-flight elastic recoil detection analysis (TOF-ERDA) to assess changes in Li concentration around the Cu/LiPON interface immediately prior to the Li plating reaction. Our electrochemical measurements indicate that critical decomposition of LiPON occurs when the voltage at the Cu electrode is reduced to 0.1 V vs. Li/Li+ at 25 °C, resulting in the in situ formation of Li3P operating at 0.7 V vs. Li/Li+ as an anode material. The TOF-ERDA findings reveal that this decomposition reaction results in a layer with partial decomposition (ranging from 5 to 25% on average) extending up to approximately 30 nm from the Cu/LiPON interface. This insight is vital for enhancing the design and performance of ASSBs. Graphical abstract

Enhancing electrocatalytic activity in metallic thin films through surface segregation of carbon.

Thin layers of commonly used adhesion metals i.e., Cr and Ti were annealed to investigate and estimate their impact on the electrochemical properties of the carbon nanomaterials grown on top of them. The microstructure, surface chemistry, and electrochemical activities of these materials were evaluated and compared with those of as-deposited thin films. The results from X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, grazing incidence X-ray diffraction (GIXRD), time-of-flight elastic recoil detection analysis (TOF-ERDA), and conductive atomic force microscopy (C-AFM) indicated the formation of a catalytic graphite layer on Cr following annealing, while no such layer was formed on Ti. This is attributed to the formation of the Cr2O3 layer on annealed Cr, which acts as a barrier to carbon diffusion into the underlying Cr. Conversely, Ti exhibits a high solubility for both carbon and oxygen, preventing the formation of the graphite layer. Cyclic voltammetry results showed that annealed Cr electrodes are electrochemically active towards both dopamine (DA) and ascorbic acid (AA) while no electrochemical activity is exhibited by annealed Ti. Quantum chemical calculations suggested that the presence of carbon as graphene or an amorphous form is critical for the oxidation reaction of probes. These results are significant for comprehending how the distinct solubilities of typical interstitial solutes influence the microstructure of adhesion metal layers and consequently yield diverse electrochemical properties.

Pathway to high performance, low temperature thin-film solid oxide cells grown on porous anodised aluminium oxide

Reversible solid oxide cells (rSOCs) present a promising solution to future energy challenges through the efficient conversion between electrical and chemical energy. To date, the benefits of rSOC technology have been off-limits to portable power and electrolysis applications due to the excessive polarisation resistance of the oxygen electrode at low temperatures, characterised by high area specific resistance (ASR) values below 500 °C. In this work we demonstrate growth of symmetric and complete rSOC structures based on state-of-the-art vertically aligned nanocomposite (VAN) films grown by pulsed laser deposition (PLD) on porous Pt-coated anodised aluminium oxide (AAO) substrates. The symmetric rSOC structures give the first demonstration of an rSOC oxygen electrode with ASR below 0.1 Ωcm2 at temperatures less than 450 °C. This is achieved through oxygen vacancy tuning by annealing, as confirmed by Time-of-Flight Elastic Recoil Detection Analysis (ToF-ERDA) and Rutherford Backscattering Spectrometry (RBS) measurements. Thus, the present work describes a promising route towards future high-performance rSOC devices for portable power applications.

Molecular layer deposition of hybrid silphenylene-based dielectric film

Molecular layer deposition (MLD) offers molecular level control in deposition of organic and hybrid thin films. This article describes a new type of inorganic–organic silicon-based MLD process where Aluminium chloride (AlCl3) and 1,4-bis(triethoxysilyl)benzene (BTEB) were used as precursors. Hybrid films were deposited at a temperature range of 300 to 500 °C and high growth per cycle (GPC) up to 1.94 Å was obtained. Field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) were used to analyze the appearance of the film surface. The hybrid film was amorphous in low-magnification FESEM images but some particulates appeared in high-magnification FESEM images (200 k). Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), Time-of-flight elastic recoil detection analysis (ToF-ERDA), and X-ray photoelectron spectroscopy (XPS) were employed to analyze the structure and composition of the hybrid film. The ratio of Al/Si in the hybrid film was 0.8. The storage environment of the films affected their capacitance, dielectric constant, leakage performance, and breakdown voltage. A film stored in a high vacuum (10–6 mbar) environment had low leakage current density (< 10–6 A × cm−2 at an applied voltage of 28 V) and a dielectric constant of 4.94, which was much smaller than after storing in a humid ambient environment.Graphical abstract

Atomic Layer Deposition of Boron‐Doped Al2O3 Dielectric Films

AbstractThis paper presents preparation of boron‐doped Al2O3 thin films by atomic layer deposition (ALD) using phenylboronic acid (PBA) and trimethylaluminum (TMA) as precursors. Deposition temperatures of 160–300 °C are studied, giving a maximum growth per cycle (GPC) of 0.77 Å at 200 °C. Field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) are used to study the surface morphology and roughness of the films. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR‐FTIR), Time‐of‐flight elastic recoil detection analysis (ToF‐ERDA), and X‐ray photoelectron spectroscopy (XPS) are used to study the composition of the films. An annealing process is carried out at 450 °C for 1 h to investigate its effect on the elemental composition and electrical properties of the boron‐doped Al2O3 thin films. The boron‐doped Al2O3 70 nm thick film deposited at 200 °C has a boron content of 3.7 at.% with low leakage current density (10−9 to 10−6 A cm−2) when the film thickness is 70 nm. The dielectric constant of this boron doped Al2O3 film is 5.18.

Ion source and low energy beam transport prototyping for a single-ended heavy ion ToF-ERDA facility

We present the status of the ion source and low energy beam transport prototyping activities for a heavy ion time-of-flight elastic recoil detection analysis (ToF-ERDA) equipment, designed to accelerate a flux of 1–10 particle nano-Ampere of 40Ar6-12+ ions to 3–6MeV energy for depth profiling of light elements. The prototype injector consists of a novel permanent magnet electron cyclotron resonance ion source CUBE-ECRIS with a minimum-B quadrupole field topology, and a 90° permanent magnet dipole with adjustable field strength for charge state selection. We report experimentally measured argon beam currents as a function of the applied microwave power and ion source potential to demonstrate the feasibility of the CUBE-ECRIS as an injector for a single-ended ToF-ERDA facility with the ion source and low energy beam transport on a 500kV platform without SF6 electrical insulation. Finally, we present the design and field measurement results of the dipole magnet prototype.

Depth profiling of Cr-ITO dual-layer sample with secondary ion mass spectrometry using MeV ions in the low energy region

This work explores the possibility of depth profiling of inorganic materials with Megaelectron Volt Secondary Ion Mass Spectrometry using low energy primary ions (LE MeV SIMS), specifically 555 keV Cu2+, while etching the surface with 1 keV Ar+ ions. This is demonstrated on a dual-layer sample consisting of 50 nm Cr layer deposited on 150 nm In2O5Sn (ITO) glass. These materials proved to have sufficient secondary ion yield in previous studies using copper ions with energies of several hundred keV. LE MeV SIMS and keV SIMS depth profiles of Cr-ITO dual-layer are compared and corroborated by atomic force microscopy (AFM) and time-of-flight elastic recoil detection analysis (TOF-ERDA). The results show the potential of LE MeV SIMS depth profiling of inorganic multilayer systems in accelerator facilities equipped with MeV SIMS setup and a fairly simple sputtering source.

Atomic Layer Deposition of Intermetallic Fe4Zn9 Thin Films from Diethyl Zinc.

We present a new type of atomic layer deposition (ALD) process for intermetallic thin films, where diethyl zinc (DEZ) serves as a coreactant. In our proof-of-concept study, FeCl3 is used as the second precursor. The FeCl3 + DEZ process yields in situ crystalline Fe4Zn9 thin films, where the elemental purity and Fe/Zn ratio are confirmed by time-of-flight elastic recoil detection analysis (TOF-ERDA), Rutherford backscattering spectrometry (RBS), atomic absorption spectroscopy (AAS), and energy-dispersive X-ray spectroscopy (EDX) analyses. The film thickness is precisely controlled by the number of precursor supply cycles, as expected for an ALD process. The reaction mechanism is addressed by computational density functional theory (DFT) modeling. We moreover carry out preliminary tests with CuCl2 and Ni(thd)2 in combination with DEZ to confirm that these processes yield Cu–Zn and Ni–Zn thin films with DEZ as well. Thus, we envision an opening of a new ALD approach based on DEZ for intermetallic/metal alloy thin films.

Effect of low-energy ion assistance on the properties of sputtered ZrB2 films

Zirconium diboride (ZrB2) films have been deposited by direct current magnetron sputtering (DCMS) from a ZrB2 compound target on Al2O3 (0001) substrates held at 600, 700, 800, and 900 °C, and with two different axial magnetic field strengths, 34 and 104 G, generated using a coil surrounding the substrate. Plasma probe measurements show an increase of the ion fluxes on floating-potential substrates of the two different configurations by a factor of 2.8 for 104 G compared to 34 G, while the ion energy remained relatively constant at ≈12 eV. Time-of-flight elastic recoil detection analysis (ToF-ERDA) show that films deposited with a magnetic field of 34 G are highly overstoichiometric with B/Zr ratios ≈2.4, while films deposited with 104 G exhibit a B/Zr ratios ≈2.1. The levels of oxygen and carbon in the films are below 1 at. % irrespective of growth conditions. X-ray diffraction (XRD) θ/2θ scans, complemented by pole figure measurements, reveal that all deposited films are 0001-oriented. XRD θ/2θ scans of the 000ℓ peak intensities and ω (rocking-curve) widths show increased ZrB2 crystal quality with increasing temperature for both magnetic field strengths. Minimum electrical resistivity of ≈100 μΩcm is achieved for an axial magnetic field of 104 G, independent of temperature.

Systematic compositional analysis of sputter-deposited boron-containing thin films

Boron-containing materials exhibit a unique combination of ceramic and metallic properties that are sensitively dependent on their given chemical bonding and elemental compositions. However, determining the composition, let alone bonding, with sufficient accuracy is cumbersome with respect to boron, being a light element that bonds in various coordinations. Here, we report on the comprehensive compositional analysis of transition-metal diboride (TMBx) thin films (TM = Ti, Zr, and Hf) by energy-dispersive x-ray spectroscopy (EDX), x-ray photoelectron spectroscopy (XPS), time-of-flight elastic recoil detection analysis (ToF-ERDA), Rutherford backscattering spectrometry (RBS), and nuclear reaction analysis (NRA). The films are grown on Si and C substrates by dc magnetron sputtering from stoichiometric TMB2 targets and have hexagonal AlB2-type columnar structures. EDX considerably overestimates B/TM ratios, x, compared to the other techniques, particularly for ZrBx. The B concentrations obtained by XPS strongly depend on the energy of Ar+ ions used for removing surface oxides and contaminants prior to analyses and are more reliable for 0.5 keV Ar+. ToF-ERDA, RBS, and NRA yield consistent compositions in TiBx. They also prove TiBx and ZrBx films to be homogeneous with comparable B/TM ratios for each film. However, ToF-ERDA, employing a 36-MeV 127I8+ beam, exhibits challenges in depth resolution and quantification of HfBx due to plural and multiple scattering and associated energy loss straggling effects. Compared to ToF-ERDA, RBS (for the film grown on C substrates) and NRA provide more reliable B/Hf ratios. Overall, a combination of methods is recommended for accurately pinpointing the compositions of borides that contain heavy transition metals.

Atomic layer deposition of TbF3 thin films

Lanthanide fluoride thin films have gained interest as materials for various optical applications, including electroluminescent displays and mid-IR lasers. However, the number of atomic layer deposition (ALD) processes for lanthanide fluorides has remained low. In this work, we present an ALD process for TbF3 using tris(2,2,6,6-tetramethyl-3,5-heptanedionato)terbium and TiF4 as precursors. The films were grown at 175–350 °C. The process yields weakly crystalline films at the lowest deposition temperature, whereas strongly crystalline, orthorhombic TbF3 films are obtained at higher temperatures. The films deposited at 275–350 °C are exceptionally pure, with low contents of C, O, and H, and the content of titanium is below the detection limit (&amp;lt;0.1 at. %) of time-of-flight elastic recoil detection analysis (ToF-ERDA). Due to the lack of titanium impurities, the films show high transmittance down to short UV wavelengths.

Al2O3 ALD films grown using TMA + rare isotope 2[formula omitted]O and 1[formula omitted]O precursors

In this work hydrogen and oxygen migration and exchange reactions in the atomic layer deposited (ALD) Al2O3 thin films were studied together with hydrogen incorporation by varying deposition parameters. Al2O3 films deposited at low temperatures can contain more than 20 at.% of hydrogen. Both higher temperature and longer purge length decrease the hydrogen and carbon concentrations significantly. In order to track the hydrogen and oxygen movement in the films, heavy water (2H216O) and oxygen-18 enriched water (1H218O) were used as precursors in combination with trimethylaluminium (TMA). Different isotopes of the same element were quantified by means of time-of-flight elastic recoil detection analysis (ToF-ERDA). It was found out that 1H/2H exchange reactions take place even at room temperature if the hydrogen concentration is high enough. On the other hand, oxygen atoms in the films do not migrate notably.

Time-Of-Flight ERDA for Depth Profiling of Light Elements

The time-of-flight elastic recoil detection analysis (TOF-ERDA) method is one of the ion beam analysis methods that is capable of analyzing light elements in a sample with excellent depth resolution. In this method, simultaneous measurements of recoil ion energy and time of flight are performed, and ion mass is evaluated. The energy of recoil ions is calculated from TOF, which gives better energy resolution than conventional Silicon semiconductor detectors (SSDs). TOF-ERDA is expected to be particularly applicable for the analysis of light elements in thin films. In this review, the principle of TOF-ERDA measurement and details of the measurement equipment along with the performance of the instrumentation, including depth resolution and measurement sensitivity, are described. Examples of TOF-ERDA analysis are presented with a focus on the results obtained from the measurement system developed by the author.

Ionic conductivity in LixTaOy thin films grown by atomic layer deposition

The material system Li-Ta-O is a promising candidate for thin-film solid-state electrolytes in Li-ion batteries. In the present study, we have varied the Li content x in LixTaOy thin films grown by atomic layer deposition (ALD) with the aim of improving the Li-ion conductivity. The amorphous films were grown at 225 °C on insulating sapphire and on conductive Ti substrates using tantalum ethoxide (Ta(OEt)5), lithium tert-butoxide (LiOtBu) and water as reactants. The film composition was determined by time-of-flight elastic recoil detection analysis (TOF-ERDA), displaying an almost linear relationship between the pulsed and deposited Li content. The ionic conductivities were determined by in-plane and cross-plane AC measurements, exhibiting an Arrhenius-type behaviour and comparatively weak thickness-dependence. Increasing Li content x from 0.32 to 0.98 increases the film conductivity by two orders of magnitude while higher Li content x = 1.73 results in decreased conductivity. A room-temperature conductivity σRT of ~10−8 S cm−1 is obtained for a 169 nm thick Li0.98TaOy film. The evolution of conductivity and activation energy suggests a competing effect between the concentration and the mobility of mobile Li ions when more Li are incorporated. The compositional dependence of Li transport mechanism is discussed.

(Invited) Wet-Chemical Etching of III-V Semiconductors: Towards Atomic-Layer-Scale Processing

Recent developments in device technology resulted in an upsurge of interest in III-V compound semiconductors. These include improved fabrication techniques for flexible electronic devices,[1,2] and epitaxial integration of various III-V channel materials on Si-based platform wafers enabling the development of highly scaled CMOS transistors [3–5] and nanophotonic devices [6]. While fabrication strategies for traditional III-V optoelectronic devices such as light-emitting diodes, lasers and solar cells are well established, the very small dimensions of these new nanodevices pose new problems. In such applications wet-chemical etching remains an essential step. The ever decreasing size of III-V devices requires ultimately atomic-layer-scale control of surfaces in terms of etching selectivity, stoichiometry and morphology.[7,8] Considerable expertise and literature is currently available on III-V semiconductor etching[9,10]. However, much of the reported work is empirical, etch rates are high, and mechanistic insight into (electro)chemical processes occurring at the semiconductor-solution interface is often lacking. In this work an overview will be given of wet-chemical approaches for nanoscale and atomic-layer-scale etching of Ga(In)As and InP. Two types of etching systems will be discussed. The first is based on the use of acidic H2O2 solution. Inductively coupled plasma mass spectrometry (ICP-MS) measurements, used to determine etching kinetics, showed that under similar conditions the etch rate of Ga(In)As in H2SO4/H2O2 solution is more than an order of magnitude higher than that of InP. Another striking observation is the influence of the acid, H2SO4 and HCl, on etching kinetics. An increase in HCl concentration leads to an increase in the etch rate of InP while the dissolution rate of Ga(In)As is markedly lowered for the active etching range. Previous work suggested that the surface oxide or hydroxide may be important.[11,12] We have used X-ray photoemission spectroscopy (XPS) and time-of-flight elastic recoil detection analysis (ToF-ERDA) to obtain information about (hydr)oxide formation on the etched surfaces. ToF-ERDA measurements also allowed us the detect surface chlorine in the case of HCl-based etchants. The results indicate that, while the initial step (the breaking of the III-V surface bond) is the same for both semiconductors, the ease with which the resulting group V hydroxide entity at the surface can be deprotonated determines whether the etch rate will be high (Ga(In)As) or low (InP). The mechanism can also help to explain the contrasting role of HCl in the dissolution of the two semiconductors. An alternative digital type of etching approach for InGaAs and InAs involves self-limiting surface oxidation in O3/H2O followed by an oxide removal step in HCl solution[12]. ICP-MS quantification of the dissolved surface oxide species indicates that a high stoichiometry of etching is obtained and that the number of equivalent oxidized atomic layers can be controlled by adjusting the dissolved O3 concentration. For >4 cycles some surface roughening is observed, most likely due to due to the high solubility of As oxides in water. An important advantage of the 2-step approach is that defect selective etching can be effectively suppressed. Examples of applications of the two etching systems will be highlighted. [1] C.-W. Cheng, K.-T. Shiu, N. Li, S.-J. Han, L. Shi, D.K. Sadana, Nat. Commun. 4 (2013) 1577. doi:10.1038/ncomms2583[2] N.J. Smeenk, J. Engel, P. Mulder, G.J. Bauhuis, G. Bissels, J.J. Schermer, E. Vlieg, J.J. Kelly, ECS J. Solid State Sci. Technol. 2 (2013) P58–P65.[3] J.A. del Alamo, Nature. 479 (2011) 317–323. doi:10.1038/nature10677[4] M. Paladugu, C. Merckling, R. Loo, O. Richard, H. Bender, J. Dekoster, W. Vandervorst, M. Caymax, M. Heyns, Cryst. Growth Des. 12 (2012) 4696–4702. doi:10.1021/cg300779v[5] N. Waldron, C. Merckling, L. Teugels, P. Ong, S.A.U. Ibrahim, F. Sebaai, A. Pourghaderi, K. Barla, N. Collaert, A.V.-Y. Thean, IEEE Electron Device Lett. 35 (2014) 1097–1099. doi:10.1109/LED.2014.2359579[6] Y. Shi, Z. Wang, J. Van Campenhout, M. Pantouvaki, W. Guo, B. Kunert, and D. Van Thourhout, Optica 4, 1468-1473 (2017). doi:10.1364/OPTICA.4.001468[7] K.J. Kanarik, T. Lill, E.A. Hudson, S. Sriraman, S. Tan, J. Marks, V. Vahedi, R.A. Gottscho, J. Vac. Sci. Technol. Vac. Surf. Films. 33 (2015) 020802. doi:10.1116/1.4913379[8] G.S. Oehrlein, D. Metzler, C. Li, ECS J. Solid State Sci. Technol. 4 (2015) N5041–N5053. doi:10.1149/2.0061506jss[9] P.H.L. Notten, J.E.A.M. Meerakker, J.J. Kelly, Elsevier Advanced Technology, 199.[10] A.R. Clawson, Mater. Sci. Eng. R Rep. 31 (2001) 1–438[11] D.H. van Dorp, S. Arnauts, D. Cuypers, J. Rip, F. Holsteyns, S.D. Gendt, J.J. Kelly, ECS J. Solid State Sci. Technol. 3 (2014) P179–P184. doi:10.1149/2.021405jss[12] D.H. van Dorp, S. Arnauts, F. Holsteyns, S.D. Gendt, ECS J. Solid State Sci. Technol. 4 (2015) N5061–N5066. doi:10.1149/2.0081506jss

Ion beam measurements for the investigation of TiN thin films deposited on different substrates by vacuum arc discharge

Titanium nitride thin films were deposited on different substrates using vacuum arc discharge system. Simultaneous ion beam analysis measurements including elastic backscattering (EBS) and nuclear reaction analysis (NRA); were applied for both composition analysis and thickness measurements of the prepared TiN films. Experimental conditions have been optimized to avoid overlapping of peaks of different nuclear reactions products, especially those related to interaction between ion beam and light elements present in totally different substrates. Independent compliment measurements utilizing time-of-flight elastic recoil detection analysis (TOF-ERDA), scanning electron microscopy (SEM) equipped with energy dispersive X-ray analysis (EDX) and X-ray diffraction (XRD) measurements were also applied to verify the experimental findings obtained by EBS and NRA measurements. The results have shown that all prepared TiN films have N/Ti ratio of around 1, with low levels of contamination elements.

Analysis of retained deuterium on Be-based films: Ion implantation vs. in-situ loading

Pure Be, Be-O and Be-O-C thin coatings were deposited using high-power impulse magnetron sputtering (HiPIMS) with and without incorporation of deuterium. The coatings produced without deuterium were implanted afterwards with 15 keV 2H+ ion beams with a fluence limited to 2 × 1017 ion/cm2 in order to mitigate the damage imposed by ion irradiation and prevent a fast gas release. The as-deposited and as-implanted coatings were analysed by IBA techniques, namely by elastic and Rutherford backscattering spectrometries (EBS and RBS, respectively), nuclear reaction analysis (NRA) and by time-of-flight elastic recoil detection analysis (ToF-ERDA). Despite distinct deuterium depth profiles in the implanted samples, the results show that for the present ion implantation and deposition parameters, similar retained amounts are revealed in the films loaded by ion implantation or during the HiPIMS deposition, assuring ion implantation as a competitive and reliable method for fuel incorporation in thin Be-based films for retention studies in controlled conditions.

Tungsten surface enrichment in EUROFER and Fe-W model systems studied by high-resolution time-of-flight rutherford backscattering spectroscopy

Time-of-flight Rutherford backscattering spectroscopy (ToF-RBS) with incident heavy ions offers a substantially improved depth resolution compared to conventional RBS with incident He ions. The new Garching ToF-RBS detector is located at a scattering angle of 150° with a free flight path of 1.313 m and a time resolution of 600 ps. The experimentally achieved depth resolution at the surface of W-containing Fe samples is 2–3 nm using incident Si ions. Model systems consisting of Fe layers with 0.7, 1.5 and 4.2 at% W and EUROFER steel (containing 0.34 at% W + Ta) were eroded by 200 eV D ions to a fluence of 1023 D/m2 at 310 K and 900 K. W depth profiles were measured using ToF-RBS, light impurities at the surface were detected using time-of-flight elastic recoil detection analysis (ToF-ERDA). The data sets from the two techniques were analyzed self-consistently. In all cases W enrichment at the surface was observed. The enrichment at 310 K is in good agreement with SDTrimSP simulations if the experimentally achieved depth resolution is taken into account. Annealing of the model systems with 0.7 and 1.5 at% W to 900 K for 10 h in vacuum resulted also in a W-enriched surface layer.

Ion-beam based characterization of TiN back contact interlayers for CZTS(e) thin film solar cells

Time-of-Flight Elastic Recoil Detection Analysis (ToF-ERDA) and Time-of-Flight Medium-Energy Ion Scattering (ToF-MEIS) have been employed to investigate the potential of TiN thin films as intermediate layers on Mo back contact in CZTS(e) solar cells. TiN films of various thicknesses (20, 50 and 200 nm) were prepared with reactive DC magnetron sputtering and atomic layer deposition on Mo/SLG (soda-lime glass) substrates and annealed ex situ in either S or Se atmosphere. In situ annealing of the samples to different temperatures was also performed in the MEIS setup together with subsequent ToF-MEIS and ERDA analysis.The results of the sample and interlayer composition profiles, layer quality and thickness distributions are discussed in context with complementary experimental findings partially obtained previously by X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD), Scanning Electron Microscopy and Scanning Transmission Electron Microscopy – Electron Energy Loss Spectroscopy (STEM – EELS).

Surface analysis and depth profiling using time-of-flight elastic recoil detection analysis with argon sputtering

The recent development of new advanced materials demands extensive effort in developing new analytical techniques that can provide insight into material composition at the nanoscale, particularly at surfaces and interfaces, which is important for both fabrication and material performance. Here, we present a proof of principle for a new setup used for thin-film characterisation and depth profiling based on a combination of time-of-flight elastic recoil detection analysis (TOF-ERDA) and Ar sputtering. A quantitative depth profiling with a best achievable surface depth resolution of ~2 nm can be realised for the entire layer, which is important for the precise determination of thickness and composition of samples that are several tenths of a nanometre thick. The performance of TOF-ERDA with Ar sputtering was demonstrated using 15 nm Cu evaporated onto a Si substrate. The advantages and limits of the method are discussed in detail.