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Hardness is a key property in materials' characterization, particularly regarding micro and submicron functional coating technology. Hardness definition is commonly cited as the resistance of materials to plastic deformation. To assess the hardness value of a given material different methods are available and can be defined as macro-, micro- or nano-scale according to the forces applied and the displacements obtained. Nano-hardness measurements are essential for functional thin coatings characterization. In the present work we tested the possibility to evaluate coatings hardness by using a complementary method: the ion beam sputtering by Secondary Ion Mass Spectrometry (SIMS) equipment. This approach has two evident advantages: independence of measurements from the substrate and additional compositional and structural information provided by SIMS measurements. The applicability of this approach has been experimentally tested on several kind of hard coating films (as ZrN, TiN, TiAlCN et al.), including diamond-like (DLC) carbon materials. Some initial results pointed out the possibility to find a direct relationship between hardness and sputter rate, pointing out a good agreement with previous works. Nevertheless, detailed tests showed evident problems on DLC coatings. In this case the dependence between ion beam sputter rate and hardness is not evident and far to fit other experimental data. In our hypothesis this effect is related to the different nature of hardness on DLC materials.

In the last years a lot of effort has been directed in order to reduce silicon defects eventually formed during the ion implantation/anneal sequence used in the fabrication of CMOS devices. In this work we explored the effect of ion implant dose rate and temperature on the formation of silicon defects for high fluence 49BF2 implantations. The considered processes (implantation and annealing) conditions are those typically used to form the source/drain regions of p-channel transistors in the submicron technology node and will be detailed in the document. Characterization of implant damage and extended silicon defects left after anneal has been performed by TEM. Dopant distribution and dopant activation has been investigated by SIMS and SRP analysis. We have verified that implant dose rate and temperature modulate the thickness of the amorphous silicon observed after implant, as well as the concentrations of silicon defects left after anneal. Effect of high dose rate low temperature implantation on product device was also evaluated, showing a reduction of leakage current on p-channel transistors. Experimental set up, results and possible explanation will be reported and discussed in the paper.

/Ge interface, while phosphorous dose loss and diffusion to the bulk are strongly suppressed in comparison to Gesubstrate without nitrogen implantation. Possible physical mechanisms (involving phosphorous-vacancies or phosphorous-nitrogencomplexes, and end-of-range interstitials) that explain this result are presented and discussed.© The Author(s) 2015. Published by ECS. This is an open access article distributed under the terms of the Creative CommonsAttribution Non-Commercial No Derivatives 4.0 License (CC BY-NC-ND, http://creativecommons.org/licenses/by-nc-nd/4.0/),which permits non-commercial reuse, distribution, and reproduction in any medium, provided the original work is not changed in anyway and is properly cited. For permission for commercial reuse, please email: oa@electrochem.org. [DOI: 10.1149/2.0061506ssl]All rights reserved.Manuscript submitted February 26, 2015; revised manuscript received April 9, 2015. Published April 21, 2015.

Nanostructured germanium substrates are produced by gold ion implantation; they show periodic ripples of nanometer size, decorated on the top and partially on one side with a forest of curled nanowires that end with gold-rich nanoparticles. For the first time, through a novel two-step soft lithography transfer process, the multi-scale nanopatterns are replicated, with features well below 100 nm, on biocompatible 2-norbornene ethylene cyclic olefin copolymer substrates. Given the suitable aspect ratio of the nanoripples and the peculiarity of their multiscale structure, the final substrates are available for cell–material interaction studies that can shed light on the role of the hierarchy of nanostructured materials in controlling the large-scale cellular behavior on biocompatible scaffolds. This work also presents an original combination of numerical analyses of scanning force microscopy images, which allows an accurate quantitative description of the outputs of the two-step transfer process.

In the present work diffusion of implanted nitrogen in germanium is studied as a function of implantation energy and post-implantation annealing temperature. Implantations have been performed at a constant dose and energies leading to the amorphization of the substrate. Nitrogen diffusion in Ge is anomalous (not obeying the 2nd Fick's law) towards the substrate surface on which an Al2O3 layer has been deposited before annealing for protection. There is evidence that N diffusion in Ge is interstitial-assisted and takes place in the presence of Ge interstitials gradients between the Al2O3/Ge and the former amorphous/crystalline (a/c) interface of the substrate during annealing. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

High-k dielectrics as SrxTi1-xOy (STO) are of great interest for the development of dynamic random access memory devices. The characterization of these nanolayers is important. Secondary ion mass spectrometry (SIMS) depth profiling through TiN and STO films is affected by strong artifacts in different ways. The erosion process causes surface topography modifications both in the TiN/STO/TiN layer system and in the silicon substrate. Atomic force microscopy analyses have been carried out on pristine TiN and STO film surfaces and at various crater depths. Very different roughness evolutions are identified for TiN or STO films, within the SIMS craters sputtered with 500 eV Cs+ while using eucentric stage rotation. Copyright © 2012 John Wiley & Sons, Ltd.

In this work we demonstrate the fabrication and characterization of high performance junction diodes using annealing temperatures within the temperature range of 300-350?C. The low temperature dopant activation was assisted by a 50nm platinum layer which transforms into platinum germanide during annealing. The fabricated diodes exhibited high forward currents, in excess of 400A/cm2 at ~|0.7|V for both p+/n and n+/p diodes, with forward to reverse ratio IF/IR greater than 104. Best results for the n+/p junctions were obtained at the lower annealing temperature of 300?C. These characteristics compare favorably with the results of either conventional or with Ni or Co assisted dopant activation annealing. The low-temperature annealing in combination with the high forward currents at low bias makes this method suitable for high performance/low operating power applications, utilizing thus high mobility germanium substrates.

Germanium (Ge) surfaces have been irradiated with 26 keV gold (Au) ions at a constant fluence and at incidence angles varying from 0° to 85°. The evolution of the emerging nanostructures is studied by atomic force microscopy (AFM), scanning electron microscopy, x-ray photoelectron spectroscopy (XPS), and cross-sectional transmission electron microscopy. The obtained results are compared with findings reported in the literature. Periodic rippled patterns with the wave vector parallel to the projection of the ion beam direction onto the Ge surface develop between 30° and 45°. From 75° the morphology changes from parallel-mode ripples to parallel-mode terraces, and by further increasing the incidence angle the terraces coarsen and show a progressive break-up of the front facing the ion beam. No perpendicular-mode ripples or terraces have been observed. The analysis of the AFM height profiles and slope distributions shows in the 45°-85° range an angular dependence of the temporal scale for the onset of nonlinear processes. For incidence angles below 45°, the surface develops a sponge-like structure, which persists at higher incidence angles on the top and partially on the face of the facets facing the ion beam. The XPS and the energy-dispersive x-ray spectroscopy evidence the presence of Au nano-aggregates of different sizes for the different incidence angles. This study points out the peculiar behavior of Ge surfaces irradiated with medium-energy Au ions and warns about the differences to be faced when trying to build a universal framework for the description of semiconductor pattern evolution under ion-beam irradiation.

Nanocrystalline silicon embedded in dielectric matrices is currently studied for Si-photonics, memory devices and solar cells. A common method for the preparation of silicon nanocrystals embedded in oxides is the phase separation of silicon rich oxide (SRO) in SiO 2 and Si via thermal annealing. Phase separation, nucleation and crystallization of SRO are known to depend on the thickness of the SRO layer. Here we investigate the structural changes in a sample consisting of alternated nanometer-thick SRO and SiO 2 layers - a so-called superlattice (SL)-during thermal annealing. Under a thermal treatment the material undergoes a series of modifications due to sintering, phase separation, crystallization and layer mixing. In this work we investigate these transformations in an SL grown by plasma enhanced chemical vapor deposition (PECVD) with several analytical techniques: XPS, variable angle ellipsometric spectroscopy (VASE), SIMS, and X-ray reflectivity (XRR). Both SIMS and XRR measurements clearly reveal the periodicity of the samples. XPS analysis reveals that phase separation of SRO in silicon and SiO 2 occurs in the annealing temperature range 600-925 °C. The process is accompanied by reduction in overall thickness of the samples (ongoing also at higher temperatures) as evidenced from the ellipsometric spectra. A maximum form birefringence is achieved at 925 °C and stays nearly constant until 1100 °C. Eventually, the form birefringence decreases at the highest annealing temperature of 1150 °C, which according to SIMS measurements is caused by a partial oxidation of silicon in the outermost SRO layer.

Silicon nanocrystals (Si-ncs) embedded in a dielectric matrix (e.g. Si 3 N 4 , SiO 2 ) attract significant interest for their use in silicon-based devices such as memories, light amplifiers, and light emitting diodes. Si-ncs in an SiO 2 matrix are generally obtained through thermal annealing of silicon-rich oxide (SRO) at elevated temperatures (900-1200 °C). In this study, we have investigated the composition of annealed SRO layers close to the interfaces with Si 3 N 4 , or c-Si with XPS, SIMS, and atomic force microscopy (AFM). The analyses indicate an approximately 2-nm thick Si-depleted region close to both the Si 3 N 4 and c-Si interface formed after annealing at 1050 °C. The formation of this Si-depleted layer is of importance for both electrical transport and charge storage in annealed SRO.

High concentration dopant distributions in silicon like those required to form ultra shallow junctions can affect SIMS analyses introducing matrix effects on secondary ions, otherwise not observed in more dilute regimes. In this work the effect of high arsenic concentration on negative secondary ion yield has been investigated when sputtering with a 0.5 keV Cs+ primary beam in a magnetic sector instrument. Two effects have been distinguished: the first one is a variation of matrix signals observed on as implanted samples in correspondence with the projected range, probably due to the damage induced by the high dose implant; the second is a step observed for several species and related to the arsenic distribution. The latter seems due to the effect of the active dopant on secondary ion energy distributions. A wide and well-centred energy slit can limit this effect allowing a more accurate quantification of the activated high As concentrations.

SIMS and medium energy ion scattering (MEIS) have been applied to the characterization of ultra shallow distribution of arsenic in silicon obtained by ion implantation at 1 and 3 keV and successive annealing at low temperature (lower than 700 °C). In case of heavy elements in light matrices, the MEIS ultimate depth resolution and its ability to obtain quantitative results from first principles result in a good reference for SIMS depth profiling. The comparison of the results obtained by the two techniques allows to discriminate among different SIMS quantification processes in order to individuate the best in terms of accuracy in the initial transient width and at the SiO 2 –silicon interface: the simple normalization of 28 Si 75 As − curve to the average of 28 Si 2 − results in the best agreement between SIMS and MEIS in the surface region. Moreover SIMS profile of the 3 keV as implanted sample resulted 1.9 nm shallower than correspondent MEIS profiles whereas samples annealed at either 650 °C or 700 °C for 10 s show a good alignment of the As segregation peak at the SiO 2 /Si interface. The sample annealed at 550 °C for 200 s shows a reduced shift between SIMS and MEIS measured As peak: a possible effect of the residual amorphous layer on the sputtering rate is pointed out as responsible of these different shifts.

We investigate the effect of the pre-amorphisation damage on the structural properties, and dopant diffusion behaviour of indium and carbon co-implanted layers in silicon. Ion implantation of indium and carbon in silicon was used to produce co-implanted specimens. Rutherford Backscattering Spectroscopy and Secondary Ion Mass Spectroscopy have been performed on as-implanted and annealed samples to assess in detail the structural properties of the doped layers and the diffusion behaviour. The results have been compared with data obtained for similar implants performed into crystalline silicon to achieve a deeper understanding of the mechanisms driving the diffusion of the indium in silicon in presence of co-implanted species. In particular a reduction of the indium diffusion and a saturation level for the indium substitutional retained dose were observed.

Due to the sensitivity, the good depth resolution and the great interest in ultra shallow profile, secondary ion mass spectrometry (SIMS) is one of the prime techniques used in the semiconductor industry. Low impact energy beams are required to profile shallow distributions. Since Cs þ beam sputtering can cause morphological artifacts as well as O2 þ beam does, a detailed study is required to understand development and limiting analytical conditions. In this work we analyzed the effect of low energy Cs þ primary beam incident at 688 and 788 on different silicon samples. By using atomic force microscopy (AFM) and scanning electron microscopy (SEM) we underline their reliability and correlate the morphological effects to the SIMS analytical parameters and samples characteristics. # 2004 Elsevier B.V. All rights reserved.

In the present work the effect induced by a thin silicon oxide and its interface with silicon on the quantification of ultra-shallow arsenic distributions measured by secondary ion mass spectrometry (SIMS) has been studied. Three As implants on a 11 nm SiO2/Si stack have been measured: the projected ranges of the arsenic implants were chosen to result in the implants being in oxide, at the SiO2/Si interface and just beyond the interface, respectively. The measurements have been performed by different analytical methodologies using Cs+ primary ions at varying impact energies and collecting the molecular species SiAs−. Different methods of normalization have been studied and the effect of the oxide on RSF variation and dose measurement has been discussed.

Preliminary total cross section data for positron scattering on argon and krypton between 250 and 5000 eV are presented. A Ramsauer-type apparatus, previously used for electron-scattering measurements has been modified. To check for the convergence between electron and positron total cross sections, a semiempirical analysis has been applied. The analysis for argon indicates an asymptotic convergence for electron and positron projectiles – the high energy parameters of the both fits are equal within the uncertainty limits. No such a clear conclusion is possible with the present data up to 5000 eV for krypton.

Thin oxides deposited by low-pressure chemical vapour deposition (LPCVD) at high temperature are being widely investigated in VLSI technology to be used as possible substitutes for the usual thermal oxides. High-temperature oxide deposition involves reactions between N 2 O and dichlorosilane or silane. Considering possible active dielectric applications, the effect of further nitridation and annealing of deposited films has to be considered. Evaluation of the nitrogen content and the distribution profile of these dielectrics then becomes a relevant analytical issue. Moreover, it is also crucial to monitor the amount of possible contaminant species, such as chlorine, introduced by the precursor gases during the deposition. In this work we present the development of an analytical methodology for quantitative depth profiling of chlorine in thin oxides using SIMS and XPS. In addition, the evolution of chlorine distribution in an appropriate set of high-temperature oxide films submitted to nitridation and further thermal processes will be shown.

In the last years a lot of effort has been directed in order to reduce ion implantation damage, which can be detrimental for silicon device performances. Implantation's dose rate and temperature were found to be two important factors to modulate residual damage left in silicon after anneal. In this work high dose rate, low temperature, high dose arsenic and boron implantations are compared to the corresponding low dose rate, room temperature processes in terms of silicon lattice defectiveness and dopant distribution, before and after anneal is performed. The considered implant processes are the one typically used to form a source/drain region in a CMOS process flow in the submicron technology node. A spike anneal process was applied to activate the dopant. Low temperature, high dose rate implantations have found to be effective in reducing silicon extended defects with a negligible effect on the profile of the activated dopant. Experimental set up, results and possible explanation will be reported and discussed in the paper.

Optimization of oblique incidence ultra low energy O2+ SIMS analysis of ultra shallow boron distributions has been investigated varying the atmosphere in the analysis chamber (ultra high vacuum or oxygen flooding) and evaluating the effect of a rotating stage allowing a 20 rpm rotation during the analysis. The impact of the different analytical approaches to the ripple formation on the crater bottom has been investigated on a boron delta doped silicon sample by AFM analysis. The combined use of a 0.5 keV O2+ beam at 68° of incidence with oxygen flooding and stage rotation of 20 rpm gave a decay length of 2.0 nm/decade at 60 nm depth without any appreciable detection of variation of sputtering rate.

We report the effect of neodymium (Nd) doping of TiO2 thin films produced on quartz, soda lime and silicon substrates by RF co-sputtering of two targets of TiO2 and metallic Nd. The Nd/Ti ratio was varied in the range of 0.9–100 at.%. A study based on a joint use of Auger electron spectroscopy and X-ray fluorescence analysis allowed us to define the chemical composition of all the deposited films. A piece of direct evidence of the structural changes (phase transformation from anatase to rutile for Nd/Ti atomic ratio up to 43 at.%) and amorphization for an Nd/Ti ratio equal to 100 at.%, a lattice distortion due to Nd incorporation and also the rare-earth ion location site was obtained by X-ray diffraction studies, in correlation with the optical properties analysis. NIR photoluminescence properties of the doped films in the wavelength range of 800–1200 nm were investigated by direct (green, blue-green and blue lines at 514.5, 496 and 476 nm respectively) and indirect excitations of Nd (using the UV line at 355 nm), in the latter case excitation through the titania host. In both cases, an intense NIR photoluminescence was observed at 907 and 1093 nm pertaining to the transitions between the excited 4F3/2 to 4I9/2 and 4I11/2 levels of the Nd3+ ions for the lowest ion concentration (Nd/Ti ratio equal to 0.9 at.%) and a correlation between the phase structure of the matrix and Nd concentration and the emission properties was found.

WOS: 000248485100095, Depth profiles of Si nanocrystals formed in sapphire by ion implantation and the effect of charging during X-ray Photoelectron Spectroscopy (XPS) and Secondary Ion Mass Spectrometry (SIMS) measurements have been studied. Atomic concentration and the chemical environment of Si, Al, and O have been measured as a function of depth from the sample surface by SIMS and XPS. Both as-implanted and annealed samples have been analyzed to understand the effect of nanocrystal formation on the depth distribution, chemical structure, and the charging effect before and after the formation process. SIMS measurements have revealed that the peak position of the Si concentration shifts to deeper values with implantation dose. This is explained by the fact that the structure of the matrix undergoes a phase transformation from pure sapphire to a Si rich amorphous Al2O3 with heavy dose implantation. Formation of Si nanocrystals has been observed by XPS by an increase in the Si-Si signal and a decrease in Si-O bond concentrations after the annealing. Variation in binding energies of Si and O with Si concentration (i.e., with depth) has been studied in terms of chemical environments and charging effects. It is found that binding energy of these elements shifts to lower values with increasing Si content. This is a result of less charging due to the presence of easy discharge paths in the Si rich regions of the matrix. Nanocrystal formation leads to even less charging which is probably due to the further increase in conductivity with the formation

The formation of boron interstitial clusters is a key limiting factor for the fabrication of highly conductive ultrashallow doped regions in future silicon-based device technology. Optimized vacancy engineering strongly reduces boron clustering, enabling low-temperature electrical activation to levels rivalling what can be achieved with conventional preamorphization and solid-phase epitaxial regrowth. An optimized 160keV silicon implant in a 55∕145nm silicon-on-insulator structure enables stable activation of a 500eV boron implant to a concentration ∼5×1020cm−3.

Forming highly stable, low resistive, ultra shallow p‐type junctions is well known to be a challenge for future transistor devices. This paper investigates the junction stability of boron layers formed with an optimized 160keV silicon vacancy engineering implant in SOI. It is demonstrated that when the electrical activation is well above the solid solubility a combination of diffusion and possible boron precipitation, during prolonged annealing at 850°C, drives the boron to return to an equilibrium level of electrical activation, which is compensated by the carrier mobility to maintain a constant Rs. Reducing the anneal temperature to 700°C shows it is possible to create highly stable p‐type junctions in terms of diffusion and sheet resistance.

As CMOS devices scale into the 45 nm process window, the requirements for the individual devices become even more stringent, with levels of activation well above solid solubility with minimal dopant diffusion. Boron interstitial clusters (BICs) are known to hinder the activation of typical boron implants reducing the level of activation even below solid solubility. This paper reports on an optimised vacancy engineering technique to reduce the interstitial population, which would normally occur after ion implantation. Hence, the BIC formation is suppressed creating a highly active layer, which remains active over a 700-1000 degrees C temperature window. Using this technique, it has been estimated that at 700 degrees C the level of activation may be around 5 x 10(20) cm(-3) rivaling techniques such pre-amorphisation combined with solid phase epitaxy re-growth. (c) 2005 Elsevier B.V. All rights reserved. Symposium on Materials Science and Device Issues for Futrue Si-Based Technologies held at the 2005 EMRS Meeting, May 31-Jun 03, 2005, Strasbourg, France

In this work we investigate the diffusion and the electrical activation of In at oms implanted into silicon with energies ranging from 40 to 360 keV and doses of 5310 12 and 5310 13 In/cm 2 during rapid thermal processing. Our investigation shows a clear dependence of In outdiffusion and electrical activation on the imp lant depth. For a fixed dose, the electrical activation was found to increase wi th the implant energy. We propose that the data can be explained by considering the balance between the local In concentration and the C background. The occurre nce of coupling between the C present in the substrate and the implanted In, dep ending on the C/In ratio, may in fact give rise to significant formation of CIn complexes. Such complexes play a role in the enhanced electrical activation due to the shallower level they introduce into the Si band gap (Ev+0.111 eV), with respect to the rather deep level (Ev+0.156 eV) of In alone [R. Baron et al., App l. Phys. Lett. 30, 594 (1977); R. Baron et al., ibid. 34, 257 (1979)]. The inter action of In atoms with the C background inside the silicon substrate has been, therefore, identified as the most likely origin of this behavior. In and C coimp lantation has also been studied in this work, in order to further investigate th e key role of C in the increase of electrical activation. A large increase of el ectrical activation has been detected in the coimplanted samples, up to a factor of about 8 after annealing at 900 °C. However, C precipitation occurs at 1100 ° C, and has dramatic effects on the carrier concentration that falls by even two orders of magnitude. This limits the maximum thermal budget that can be used for In activation in C coimplanted material.

The progressive microelectronics downscaling requires ultra-shallow junctions (USJ) in order to produce future devices. Dynamic-SIMS (D-SIMS) has been widely used to analyse dopant implants, but at the present the USJ characterisation is one of the major challenges for SIMS (secondary ion mass spectrometry) depth profiling. In this work, SIMS depth profiles have been carried out on arsenic implants at different energies in order to evaluate the most suitable analytical conditions. Analyses have been performed using both magnetic sector and time-of-flight mass spectrometer instruments.

In this work secondary ion mass spectrometry (SIMS), variable angle spectroscopy ellipsometry (VASE) and atomic force microscopy (AFM) are used to investigate the structure, composition and morphology of multilayer SRON films. Three/four SRON sequential layers were deposited on silicon wafers by PECVD and silicon, nitrogen and oxygen content was varied by changing the N2O/SiH4 ratio. The total thickness of the resulting SRON stack is about 50nm. SIMS analyses of NCs+, OCs+, SiCs+, in MCs+ methodology are performed by a Cameca SC-ultra instrument. Depth profiles are obtained at 500eV of primary beam impact energy with sample rotation. An approximate method to obtain silicon concentration is used. Total layer thickness are obtained from both SIMS and VASE measurements. In addition, we compare the thickness of the single layers obtained from VASE with the SIMS depth profiles. A detailed analysis of films morphology is obtained by AFM. The SRON stack is sputtered by SIMS until a certain layer is exposed, which is then analyzed by AFM. The sputtered layers are then etched in HF solution to better resolve the exposed nano-crystals.

In the search for a chemical sensing strategy to monitor atomic layer deposition (ALD) processes suitable for real-time application in wafer manufacturing, we have applied downstream mass spectrometry sampling to study process dynamics during ALD cycles for tungsten deposition from WF6 and SiH4. The ALD reactor has UHV cleanliness conditions and incorporated a minireactor chamber to simulate the small reaction volume anticipated for manufacturing tools to achieve adequate throughput. Mass spectrometry revealed essential surface reaction dynamics through real-time signals associated with by-product generation as well as reactant introduction and depletion for each ALD half-cycle. These were then used to optimize process cycle time and to study the effect of process recipe changes on film growth. The reaction by-products were clearly observed as H2 from SiH4 exposure and SiF4 from WF6 exposure. For each of the two half-cycles, rapid increase of by-product leds to steady-state adsorption/reaction conditions,...

The features of ultra-shallow junctions indicated by 2001 International Roadmaps require challenging characteristics for secondary ion mass spectrometry (SIMS) instruments: an ultra high depth resolution, minimization of transient width before the steady state and the ability to manage high concentration quantification in the near surface region. In this article a new magnetic sector SIMS, the Cameca Sc-Ultra, has been evaluated in order to profile boron ultra shallow junctions. In this apparatus the use of normal incidence oxygen bombardment is precluded and the primary column allows for a ⩾60° nominal incidence angle. Several approaches varying analytical parameters as energy, incidence angle and oxygen flooding have been tested on boron delta layers samples. In this way a quantitative comparison of different analytical methodologies is possible and the better analytical approach is pointed out. Moreover, an in situ laser depth profile measurement tool has been tested and the advantages and limitation a...