Sn Implantation Research Articles

Intense violet electroluminescence of thin SiO2 layers with SnO2 nanocrystals

It has been shown that Sn implantation with subsequent annealing in air leads to an increase in the electroluminescence (EL) intensity of SiO2/Si structure by two orders of magnitude. Intense violet EL with a maximum at 3.21 eV was observed at room temperature by the naked eye at forward bias. The observed emission was attributed to radiative recombination in SnO2 nanocrystals synthesized in SiO2 layers. The external quantum efficiency (EQE) increased with decreasing Sn concentration The maximum external quantum efficiency was found to be 0.7 % for the silica film Sn-implanted at the lowest fluence of 2.5 × 1016cm−2. The non-radiative charge transport (shunt current) through the sample and mechanism of EL excitation are discussed. It has been concluded that the Poole–Frenkel mechanism, or tunneling between traps are the most likely mechanisms of charge transport to light-emitting centers.

Comparison of GeSn alloy films prepared by ion implantation and remote plasma-enhanced chemical vapor deposition methods

Thin films of germanium-tin (GeSn) alloy with Sn content well above its equilibrium solubility limit in Ge are produced using both remote plasma-enhanced chemical vapor deposition (RPECVD) directly on silicon substrates and ion implantation of Sn into Ge. For RPECVD, the growth temperature of 302 °C resulted in fully relaxed GeSn alloys with high defect density, principally threading dislocations related to the large lattice mismatch between Si and GeSn. For the implantation case, pulsed laser melting was used to melt and crystallize the GeSn layer on a time scale of a few tens of nanoseconds. The resulting GeSn layers were also relaxed and defective, presumably again as a result of lattice mismatch with the underlying Ge lattice. However, the nature of the defects was quite different to the RPECVD method, whereby the line defects were not threading dislocations but stackinglike defects, which developed into arrays of these defects in the high Sn content region close to the surface. For the purpose of comparing RPECVD and ion-implantation methods, alloy films of similar thickness (400–450 nm) and Sn content (4.5–6.5 at. %) were examined. Film parameters (thickness, Sn content, Sn solubility, and segregation), as well as film quality and defect structures, were examined for both fabrication methods using several analytical techniques. This comparison provided us with a better physical understanding of our GeSn films and will help inform future growth/fabrication strategies targeted at minimizing defects formed in the GeSn films for the realization of optoelectronic devices.

Suppression of thermal diffusion of vacancies across p + -n junction structures in diamond. Application to SnV centers by ion implantation

This work reports on defect engineering related to optical centers in diamond by ion implantation. In particular, we demonstrate that thermal diffusion of vacancies to a few micrometers in depth can be effectively suppressed provided these are electrically charged and located within the depletion region of an abrupt p+ -n junction. The observed effect is complementary to the observations in the previous study (Favaro et al 2017 Nat. Commun. 8 15409) showing that charging of implantation-induced vacancies at such junction structures in diamond inhibits the formation of vacancy complexes in proximity to the targeted optical centers. In the present work we first generate vacancies near the surface of a low nitrogen doped CVD diamond substrate by He and C ion implantation before these are diffused by annealing at 1200∘C into the bulk. In the next step the depth distribution of NV centers generated by trapping of these vacancies is analyzed on a micron scale. For precise tuning of the implantation conditions we derived data on the boron and nitrogen doping by step etching of planar p+ resistors and p+ -n- p+ diode structures combined with electrical characterization and modeling. In the next step, tin-vacancy (SnV) centers were produced by 40 keV Sn implantation across the same junction structures at optimized conditions. In this way we observe an enhancement of the SnV yield and noticeable suppression of NV centers by diffusion and trapping of vacancies along the tracks of tin ions. Such ‘subsidiary’ NVs could significantly affect the emission of SnV and potentially other centers in the same spectral range.

Boosting propane dehydrogenation over Sn stabilizing dispersed Ptδ+ confined in Silicalite-1 at low temperature

Utilizing the confinement effect of zeolite pores to stabilize active sites has been developed for the improvement of catalytic stability and performance. Herein, a facile strategy is proposed to synthesize a Sn stabilizing dispersed Ptδ+ sites confined in zeolite pore catalyst via Ar calcination for propane dehydrogenation (PDH). 0.2Pt/0.5Sn-S-1-Ar shows excellent propylene formation rate of 10.0 mol C3H6·gPt−1·h−1 and propylene selectivity higher than 99.5% at 450 °C, and the superior catalyst stability in 200 h on-stream. And it has the lowest apparent activation energy barrier of 18.45 KJ/mol over Pt-based catalyst for PDH to our knowledge. According to systemic characterizations, it is demonstrated that the implantation of Sn into Silicalite-1 framework before introducing Pt is essential to generate the highly dispersed Ptδ+ species confined in zeolite pore, and the Ptδ+ species confined in zeolite pore with stronger propane adsorption and propylene desorption ability is responsible for superior PDH performance.

Deformation behavior and mechanical properties of rolled carbon fiber reinforced Al-matrix composites via protection with Sn layer

How to break the restriction of elongation mismatch between the continuous carbon fibers and Al matrix in the rolling process has become a major obstacle for developing the rolled carbon fiber reinforced Al matrix (CF/Al) composites with high-performance. Herein, a strategy for liquid protection was proposed to overcome the damage of continuous CFs in rolling process of Al matrix by constructing the CF/Al composites with coating structure of Sn layer ([[email protected]]/Al composites). The design on the stress distribution and CFs damage in the rolling deformation of [[email protected]]/Al composites was optimized based on the numerical simulation. The micro-computed tomography (micro-CT) reconstruction indicated that the implantation of Sn can effectively release the stress concentration in CFs to prevent the CFs broken. After the heat treatment, the transition layer with eutectic Al-Sn structure (~550 nm) formed between the Al-matrix and CF-reinforcement, which can be used as weak boundaries, benefits to the load transfer to the CF-reinforcement with an with an increase of 23% in Vickers hardness. More importantly, the tensile strength of rolled [[email protected]]/Al composites can reach 256 MPa, which are 42.2% and 68.4% higher than that of rolled Al-matrix and rolled CF/Al composites (180 MPa and 152 MPa), respectively. This study could motivate the ingenious design of CFs damage protection for developing the advanced CF/Al composites in the automotive and aerospace industries.

Surface morphology change of protective film on collector mirror related to implantation of Sn emitted from laser produced plasma in EUV light source

The change in surface morphology of an amorphous TiO2 protective film coated on a Mo/Si multilayer of an extreme ultraviolet (EUV) light collector mirror has been investigated. After long-time operation of an EUV light source, many pinholes of about 10 nm diameter were observed on the protective TiO2 film surface. Accelerated aging tests with thin film samples that simulated surface conditions on the collector mirror suggest that crystallization of the protective film induced by Sn implantation is the main cause of the formation of the observed pinholes.

Direct Structural Identification and Quantification of the Split-Vacancy Configuration for Implanted Sn in Diamond.

We demonstrate formation of the ideal split-vacancy configuration of the Sn-vacancy center upon implantation into natural diamond. Using β^{-} emission channeling following low fluence ^{121}Sn implantation (2×10^{12} atoms/cm^{2}, 60keV) at the ISOLDE facility at CERN, we directly identified and quantified the atomic configurations of the Sn-related centers. Our data show that the split-vacancy configuration is formed immediately upon implantation with a surprisingly high efficiency of ≈40%. Upon thermal annealing at 920 °C ≈30% of Sn is found in the ideal bond-center position. Photoluminescence revealed the characteristic SnV^{-} line at 621nm, with an extraordinarily narrow ensemble linewidth (2.3nm) of near-perfect Lorentzian shape. These findings further establish the SnV^{-} center as a promising candidate for single photon emission applications, since, in addition to exceptional optical properties, it also shows a remarkably simple structural formation mechanism.

Boosting Ge-Epi P-Well Mobility & Crystal Quality with Si or Sn Implantation and Melt Annealing

We investigated the effects of Sn, Si and C7 implantation into both P-well and N-well doped regions of Ge-epi on Si wafers after RTA and laser annealing, on crystal quality using XRD analysis and mobility using ALPro profiler of Active Layer Parametrics , which provides mobility and carrier concentration profiles at sub-nm resolution. SIMS analysis was also used for chemical depth analysis. XRD analysis shows improved Ge-epi crystallinity after >1.5J/cm2 laser melt annealing (liquid phase epitaxial regrowth). Since µ=1/ρqN where µ=mobility (cm2/volt-sec), ρ=resistivity (ohm-cm), q=charge of an electron and N=dopant concentration (cm3), if we assume qN=K a constant for these low dopant well regions then we can estimate change in mobility based on change in P-well or N-well resistance then compare to mobility measured by ALPro profiler. For the P-well cases doped with B=5keV at 1E13/cm2 dose for a retrograde P-well ~1E18/cm3 the Ge-epi Rs decreased to 1,600Ω/□ compared to Si at 3,400Ω/□ suggesting a hole mobility increase of 2.1x from 150cm2/V-s to 315cm2/V-s based on literature with actual measured Hall mobility of 465.2cm2/V-s, an increase of 3.1x. The 1.8J/cm2 laser melt anneal boosted P-well Hall mobility by 22% to 567cm2/V-s to a depth of 80nm and adding Sn implant improved mobility 91% to 889cm2/V-s and at a depth beyond 80nm mobility increases to 3,000cm2/V-sec. Si implant improved mobility by 43% to 667cm2/V-s to a depth of >100nm. For the N-well cases doped with P=40keV at 1E13/cm2 dose for a retrograde N-well ~1E18/cm3 the Ge-epi Rs increased to 2,000Ω/□ compared to Si at 1,600Ω/□ suggesting an electron mobility decrease of 0.8x to 216cm2/V-s rather than the expected increase of 3.3x from 270cm2/V-s for Si to 900cm2/V-s for Ge reported in the literature and expected N-well Rs of 485Ω/□. The actual Ge-epi N-well Hall mobility measured was 449cm2/V-s so only a 1.7x increase and nearly identical to the P-well mobility of 465cm2/V-s but the mobility drops off beyond a depth of 40nm. The 1.8J/cm2 laser melt anneal reduces N-well mobility to 191cm2/V-s but is uniform to a depth of 70nm. Adding Si implant had a slight decrease in mobility to 183cm2/V-s while Sn implant increases mobility to 280cm2/V-s uniformly to a depth >100nm. C7 (cluster-C) implant reduced N-well surface mobility to 50.3cm2/V-s to a depth of 30nm but then mobility increases 10x up to ~500cm2/V-s to a depth of 80nm and then drops to ~100cm2/V-s in the non-carbon N-well region as revealed by C-SIMS analysis to a depth of 110nm, therefore measuring mobility versus depth can be very critical in engineering surface and bulk mobility improvements based on chemical compositional changes in the Ge-epilayer. B-SIMS analysis shows retrograde P-well profile with 2E18/cm3 Rp at 50nm and Xj at 150nm also the Ge/Si epilayer interface. The laser melt flattens the B P-well profile to ~1E18/cm3 with a B pile-up at ~2E18/cm3 at the Ge/Si interface. C-SIMS analysis revealed only slight to no C diffusion even in the liquid Ge-melt phase while we observe 2-5% Si intermixing in the Ge-melt but no B nor P diffusion when C was present. Additional results for RTA anneals will be presented.

Boosting Ge-Epi P-Well Mobility & Crystal Quality with Si or Sn Implantation and Melt Annealing

We investigated the effects of Si, Sn and cluster-C implantation into both P-well and N-well doped regions of Ge-epi on Si wafers after laser annealing. XRD analysis shows improved Ge-epi crystallinity after >1.5J/cm2 laser melt annealing (liquid phase epitaxial regrowth) compared to sub-melt annealing (solid phase epitaxial regrowth). For the P-well case the Ge-epi Rs decreased to 1,600Ω/□ compared to Si at 3,400Ω/□ suggesting a hole mobility increase of 2.1x from 150cm2/V-s to 315cm2/V-s but actual measured Hall mobility was 650cm2/V-s to a depth of 60nm, an increase of 4.3x. The 1.8J/cm2 laser melt anneal with Si implant improved mobility uniformly to 700cm2/V-s to a depth of 100nm while Sn implant improved mobility to 900cm2/V-s from the Ge-epi surface to a depth of 70nm then increases to 3000cm2/V-s at a depth of 100nm. Measuring mobility depth profiles can be very critical in engineering surface and bulk mobility improvements which can be determined by chemical compositional changes in the Ge-epilayer especially for C where no liquid phase diffusion or movement could be detected.

Single-Photon-Emitting Optical Centers in Diamond Fabricated upon Sn Implantation

The fabrication of luminescent defects in single-crystal diamond upon Sn implantation and annealing is reported. The relevant spectral features of the optical centers (emission peaks at 593.5 nm, 620.3 nm, 630.7 nm and 646.7 nm) are attributed to Sn-related defects through the correlation of their photoluminescence (PL) intensity with the implantation fluence. Single Sn-related defects were identified and characterized through the acquisition of their second-order auto-correlation emission functions, by means of Hanbury-Brown-Twiss interferometry. The investigation of their single-photon emission regime as a function of excitation laser power revealed that Sn-related defects are based on three-level systems with a 6 ns radiative decay lifetime. In a fraction of the studied centers, the observation of a blinking PL emission is indicative of the existence of a dark state. Furthermore, absorption dependence from the polarization of the excitation radiation with about 45 percent contrast was measured. This work shed light on the existence of a new optical center associated with a group-IV impurity in diamond, with similar photo-physical properties to the already well-known Si-V and Ge-V emitters, thus providing results of interest from both the fundamental and applicative points of view.

High Electron and Hole Mobility by Localized Tensile & Compressive Strain Formation Using Ion Implantation and Advanced Annealing of Group IV Materials (Si+C, Si+Ge & Ge+Sn)

Since the 90nm node the industry has been using S/D-stressor for strain-channel formation and increased hole & electron mobility. The S/D-stressor strain-Si method required optimizing the deep S/D junction with the shallow SDE implant junction. PMOS used recess etch eSiGe for p+ S/D tensile strain with precise lateral gate overlap distance control to induce channel compressive strain for increased hole mobility in Si while NMOS n+ S/D compressive strain is formed by deep amorphous implant with carbon and stacking fault dislocation defects that induces channel tensile strain for increased electron mobility in Si. With the switch in transistor design from 2-D planar to 3-D FinFET by the industry at the 22nm and 14/16nm nodes, increasing eSiGe Ge content above 55% has reached it’s limit in strain-Si S/D-stressor of -3GPa for hole mobility improvement therefore requiring higher mobility channel material at 10nm and beyond by using: 1) relaxed >70% SiGe to 100% Ge or 2) compressive strain >50% SiGe to 100% Ge for higher hole mobility. Higher electron mobility requires: 1) relaxed >95% SiGe to 100% Ge, 2) tensile strain-Si on >25% relaxed-SiGe or 3) tensile strain >50% SiGe to 100% Ge. Using CVD epitaxial growth of SiGe and Ge requires thick SRB (strain relaxed buffer) epilayers by blanket or selective epitaxial growth but this results in threading dislocation in the 106 to 109 /cm2 level results in high n+ and p+ junction leakage. The reported targets for NMOS is 2% tensile channel strain of >1.5GPa while for PMOS, 2% compressive channel strain of >-1.5GPa at 7nm node [1]. This paper will review strain-Si and strain-Ge formation by ion implantation and advanced annealing to form tensile and compressive strain channel for improved electron and hole mobility in Group IV materials. Carbon and Si implants was used to form surface tensile strained-channel SiC, GeC and GeSi material while Ge and Sn implants was used to form surface compressive strained-channel SiGe, SiGeSn and GeSn material. Improved hole mobility (µh) by >4x and electron mobility (ue) by >2x have been reported by use of implantstrain formation [2,3]. References 1] R. Kim et al., IEDM-2015, paper 34.1. 2] J. Borland et al., IWJT-2013, paper S4-4, p.49. 3] J. Borland et al., IWJT-2015, paper S2-1, p.12.

(Invited) Challenges and Developments in GeSn Process Technology for Si Nanoelectronics

We have recently investigated and developed process technologies for Ge1-xSnx electronic applications. In this paper, we report our recent achievements in our research related to Ge1-xSnx; (1) electronic properties of defects related to Sn implantation in Ge, (2) oxidation of Ge1-xSnx epitaxial layers and electric property of metal/oxide/Ge1-xSnx gate-stack structure, (3) formation of Ni germanostanane layers on Ge1-xSnx epitaxial layer for metal/semiconductor contacts.

Characterization of Ge1-x-ySixSny Ternary Alloys – Comparison of UHV-CVD and Gas Source MBE Growth

Group-IV semiconductor alloys are attractive materials for advanced optoelectronic device applications such as integrated Si photonics, multi-junction solar cells, telecom, and infrared sensing. Over the past decade, ternary alloys of Ge1-x-ySixSny have been developed with attractive materials properties for these applications. These alloys show great promise for strain engineering or as compliant buffer layers since their band gap energy and lattice parameter can be tuned independently [1]. In addition, for sufficient levels of Sn incorporation, the fundamental optical band gap undergoes a crossover from indirect to direct transition [2-4]. The first demonstrated synthesis of Ge1-x-ySixSny was achieved via a UHV-CVD process using deuterated stanane (SnD4) and digermane (Ge2H6) precursors [5]. Low growth temperatures (T < 350 ◦C) are required to stabilize the substitutional Sn in the SiGe lattice because of the large disparity in atomic size. These deposition processes have subsequently been improved and extended to include the use of higher order group-IV hydride precursors such as Ge3H8, Si3H8, Ge4H10, and Si4H10 [6-9]. Alternative growth processes have also been developed to synthesize Ge1-x-ySixSny alloys including gas source molecular beam epitaxy (GS-MBE) [10] and ion implantation of Sn into a SiGe matrix [11].In this work, we report the electrical, optical, structural, and material characteristics of Ge1-x-ySixSny films over a range of alloy compositions. We compare the properties of films deposited by UHV-CVD with those grown by GS-MBE. The elemental compositions of these Ge1-x-ySixSny alloys, determined by X-ray photoelectron spectroscopy (XPS), are in good agreement with values measured using Rutherford backscattering (RBS). The XPS measurements also indicate that these alloys are susceptible to surface oxidation when exposed to laboratory ambient. Crystalline structural characteristics were measured with X-ray diffraction, two-dimensional reciprocal space mapping and X-ray reflectivity. Thin Ge1-x-ySixSny films (~ 300 nm) grown on Ge substrates showed coherent strain, while thicker films (~ 800 nm) showed partial strain relaxation. The thickest films (~ 1000 nm) were completely relaxed. No thickness fringes were observed in X-ray reflectivity due to negligible difference in electron density between the film and substrate.Temperature-dependent Hall-effect measurements show highly conductive layers although care must be exercised to avoid parallel conduction through the substrate for samples grown on Si or Ge wafers. We also report the first measurement of electronic traps in Ge1-x-ySixSny via deep level transient spectroscopy (DLTS) on p-n junction devices. Samples grown by UHV-CVD show two electron traps at low temperature while samples grown by GS-MBE show only one which is more than 10x weaker. Both the UHV-CVD and GS-MBE samples exhibit an activation energy of Ea=0.40 eV for the dark current for 200 K < T < 350 K. In addition, the leakage current under reverse bias conditions increases with increasing Sn content in the films.[1] V. R. D’Costa, Y.-Y. Fang, J. Tolle, J. Kouvetakis, and J. Menendez, Phys. Rev. Lett. 102, 107403 (2009).[2] D. W. Jenkins and J. D. Dow, Phys. Rev. B 36, 7994 (1987).[3] R. A. Soref and C. H. Perry, J. Appl. Phys. 69, 539 (1991)[4] J. D. Gallagher, C. Xu, L. Jiang, J. Kouvetakis, and J. Menendez, Appl. Phys. Lett. 103, 202104 (2013)[5] M. Bauer, J. Taraci, J. Tolle, A. V. G. Chizmeshya, S.Zollner, D. J. Smith, J. Menendez, C. Hu and J. Kouvetakis, Appl. Phys. Lett., 81, 2992 (2002).[6] J. Tolle, A. V. G. Chizmeshya, Y. Y. Fang, J. Kouvetakis, V. R. D’Costa, C. W. Hu, J. Men_endez, and I. S. T. Tsong, Appl. Phys. Lett. 89, 231924 (2006).[7] Y.-Y. Fang, J. Xie, J. Tolle, R. Roucka, V. R. D’Costa, A. V. G. Chizmeshya, J. Menendez, and J. Kouvetakis, J. Am. Chem. Soc. 130, 16095 (2008).[8] J. Xie, J. Tolle, V. R. D’Costa, A. V. G. Chizmeshya, J. Men_endez, and J. Kouvetakis, Appl. Phys. Lett. 95, 181909 (2009).[9] C. Xu, L. Jiang, J. Kouvetakis, and J. Men_endez, Appl. Phys. Lett. 103, 072111 (2013).[10] H. Lin, R. Chen, W. Lu, Y. Huo, T. I. Kamins, and J. S. Harris, Appl. Phys. Lett. 100, 141908 (2012).[11] G. H. Wang, E.-H. Toh, X. Wang, S. Tripathy, T. Osipowicz, T. K. Chan, K.-M. Hoe, S. Balakumar, G.-Q. Lo, G. Samudra, and Y.-C. Yeo, Appl. Phys. Lett. 91, 202105 (2007).

Interaction of Sn atoms with defects introduced by ion implantation in Ge substrate

The interaction of Sn atoms with defects induced by Sn implantation of Ge substrates with antimony (Sb) as an n-type dopant and the impact of H2 annealing on these defects were investigated by comparison with defects induced by Ge self-implantation. In the Ge samples implanted with either Sn or Ge, and annealed at temperatures of less than 200 °C, divacancies, Sb-vacancy complexes with single or double acceptor-like states, and defects related to Sb and interstitial Ge atoms were present. On the other hand, after annealing at 500 °C in an N2 or H2 atmosphere, defects with different structures were observed in the Sn-implanted samples by deep level transition spectroscopy. The energy levels of the defects were 0.33 eV from the conduction band minimum and 0.55 eV from the valence band maximum. From the capacitance-voltage (C-V) characteristics, interaction between Sn atoms and defects after annealing at 500 °C was observed. The effect of H2 annealing at around 200 °C was observed in the C-V characteristics, which can be attributed to hydrogen passivation, and this effect was observed in both the Ge- and Sn-implanted samples. These results suggest the presence of defects that interact with Sn or hydrogen atoms. This indicates the possibility of defect control in Ge substrates by Sn or hydrogen incorporation. Such defect control could yield high-performance Ge-based devices.

Interplay of ballistic and chemical effects in the formation of structural defects for Sn and Pb implanted silica

The electronic structures of Sn and Pb implanted SiO2 are studied using soft X-ray absorption (XAS) and emission (XES) spectroscopy. We show, using reference compounds and ab initio calculations, that the presence of PbO and SnO interactions can be detected in the pre-edge region of the oxygen K-edge XAS. Via analysis of this interaction-sensitive pre-edge region, we find that Pb implantation results primarily in the clustering of Pb atoms. Conversely, with Sn implantation using identical conditions, strong SnO interactions are present, showing that Sn is coordinated with oxygen. The varying results between the two ion types are explained using both ballistic considerations and density functional theory calculations. We find that the substitution of Pb into Si sites in SiO2 requires much more energy than substituting Sn in these same sites, primarily due to the larger size of the Pb ions. From these calculated formation energies it is evident that Pb requires far higher temperatures than Sn to be soluble in SiO2. These results help explain the complex processes which take place upon implantation and determine the final products.

Energetic Sn+ irradiation effects on ruthenium mirror specular reflectivity at 13.5-nm

Sn+ irradiations of Ru single-layer mirrors (SLM) simulate conditions of fast-Sn ion exposure in high-intensity 13.5 nm lithography lamps. Ultra-shallow implantation of Sn is measured down to 1–1.5 nm depth for energies between 1–1.3 keV at near-normal incident angles on Ru mirror surfaces. The Sn surface concentration reaches an equilibrium of 55–58% Sn/Ru for near-normal incidence and 36–38% for grazing incidence at approximately 63 degrees with respect to the mirror surface normal. The relative reflectivity at 13.5 nm at 15-degree incidence was measured in-situ during Sn+ irradiation. For near-normal Sn+ exposures the reflectivity is measured to decrease between 4–7% for a total Sn fluence of 1016 cm−2. Theoretical Fresnel reflectivity modeling shows for the same fluence assuming all Sn atoms form a layer on the Ru mirror surface, that the reflectivity loss should be between 15–18% for this dose. Ex-situ absolute 13.5 nm reflectivity data corroborate these results, indicating that implanted energetic Sn atoms mixed with Ru reflect 13.5-nm light differently than theoretically predicted by Fresnel reflectivity models.

Improved biological performance of low modulus Ti–24Nb–4Zr–7.9Sn implants due to surface modification by anodic oxidation

Dental implants are usually made from commercially pure titanium or titanium alloys. The purpose of this study was to evaluate the influence of surface treatment to low modulus Ti–24Nb–4Zr–7.9Sn (TNZS) on cell and bone responses. The TNZS alloy samples were modified using anodic oxidation (AD). Surface oxide properties were characterized by using various surface analytic techniques, involving scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS), X-ray diffractometry (XRD) and surface profilometer. During the AD treatment, porous titanium oxide layer was formed and Ca ions were incorporated into the oxide layer. The viability and morphology of osteoblasts on Ca-incorporated TNZS were studied. The bone responses of Ca-incorporated TNZS were evaluated by pull-out tests and morphological analysis after implantation in rabbit tibiae. The non-treated Ti and TNZS samples were used as the control. Significant increases in cell viability and pull-out forces ( p < 0.05) were observed for Ca-incorporated TNZS implants compared with those for the control groups. Porous structures supplied positive guidance cues for osteoblasts to attach. The enhanced cell and bone responses to Ca-incorporated TNZS implants could be explained by the surface chemistry and microtopography.

Photoluminescence of SnO2 nanoparticles embedded in Al2O3

Tetragonal Sn nanoparticles of ∼15 nm diameter are produced in Al2O3 by direct Sn implantation at room temperature. After thermal annealing at 1000 °C in oxygen, the implantation-induced amorphous region recrystallized and the Sn nanoparticles turned into SnO2 nanoparticles with an average diameter of ∼30 nm as revealed by transmission electron microscopy. While no absorption and photoluminescence (PL) are observed from the metallic Sn nanoparticles, SnO2 nanoparticles exhibit an absorption edge at ∼280 nm and three emission bands at 410 nm, 520 nm and 700 nm, respectively. In addition to the previously reported blue and green emission from SnO2 nanostructures, a red PL band was observed due to the unique surface state of SnO2 nanoparticles embedded in Al2O3 substrate fabricated by ion implantation.

Strained SiGeSn formed by Sn implant into SiGe and pulsed laser annealing

Incorporation of tin (Sn) in substitutional sites in strained Si0.75Ge0.25 was demonstrated by Sn implant and pulsed laser annealing. The surface of Si0.75Ge0.25 was amorphized by Sn implant but was recrystallized after pulsed laser annealing. The crystalline Si1−x−yGexSny layer formed was studied by Rutherford backscattering spectrometry and Raman spectroscopy. A substitutionality up to 62% Sn and 80% Ge was obtained at an optimal laser power of 400mJcm−2 for five laser pulses. A compressive strain of −1.15% was also obtained due to Sn incorporation. The presence of Sn also increased the active B dopant concentration in activating Si1−x−yGexSny to give low sheet resistance. The implantation of Sn and B followed by pulsed laser annealing could be useful for application in strain engineering of high mobility metal-oxide-semiconductor field-effect transistors.

Formation and growth of SnO2 nanoparticles in silica glass by Sn implantation and annealing

Nanocrystalline Sn particles have been formed in silica glass through 50 keV Sn− implantation followed by annealing in N2 at 650 °C for 30 min. Samples prepared this way have been annealed in air for 1 h, separately at four different temperatures, 400, 600, 800, and 1000 °C, each at a given temperature. Annealing at temperatures higher than 400 °C has been found to result in oxidation of the Sn nanoparticles (NPs) and formation of the SnO2 phase as confirmed from optical absorption (OA), transmission electron microscopy, and Raman scattering measurements. For the sample annealed at 600 °C, Raman scattering data showed three bands at about 525, 629, and 771 cm−1, the last two corresponding to the A1g and B2g classical Raman modes of rutile SnO2. Increase in annealing temperature resulted in an increase in the intensities of the A1g and B2g modes showing better crystallinity. Also, the A1g peak shifted toward a higher wave number with a steady decrease in the intensity at 525 cm−1. This is in line with the growth in size of NPs as well as a reduction in the surface disorder. The Urbach tail width derived from the OA data also agrees with this.