Solid-phase Recrystallization Research Articles

Structure of Silicon Wafers Planar Surface before and after Rapid Thermal Treatment

Presently it is important to remove mechanically disturbed layer on wafer surface during creation of up-to-date microelectronic products. Rapid thermal treatment with optical pulses of second duration is one of the applicable methods for removing disturbances in crystal lattice emerging after ion implantation. However the crystal structure of mechanically disturbed layer on wafer planar side is still unclear. Researches by transmission electronic method, analysis of diffraction reflection curve and electronic Auger spectroscopy has failed to provide reliable data about the state of crystal lattice in surface layer of at least 30 nm thickness. Hence it was impossible to suggest a model of solid phase recrystallization and to present its mathematical description. The goals of the work were as follows: – identify of silicon crystal lattice state in surface layer of 30 nm thickness before and after rapid thermal treatment by backward reflected electrons diffraction method using raw Si wafers surface; – analysis of contamination element composition on the surface of raw silicon before and after rapid thermal treatment; – model development for solid phase recrystallization of surface disturbed layer after rapid thermal treatment and its mathematical description. Images of back ward reflected electrons diffraction using surface layer of raw silicon wafers' of 30 nm thickness and also the results of the planar surface of raw silicon wafers' cleaning from impurities are provided. Processes reducing the activating energy of mechanically disturbed silicon layer recrystallization process were suggested and its mathematical description was provided. Parameters of rapid thermal treatment mitigating the thermal impact on silicon wafer for recrystallization of mechanically disturbed layer on its planar surface ware defined.

Local laser-induced solid-phase recrystallization of phosphorus-implanted Si/SiGe heterostructures for contacts below 4.2 K

Local laser-induced solid-phase recrystallization of phosphorus-implanted Si/SiGe heterostructures for contacts below 4.2 K

Hydrothermal synthesis and sorption performance to Cs(I) and Sr(II) of zirconia-analcime composites derived from coal fly ash cenospheres

The paper is concerned with (i) the hydrothermal synthesis of hydrous zirconium dioxide (HZD) bearing analcime (HZD-ANA, zirconia-analcime) and (ii) its sorption properties with respect to Cs+ and Sr2+. The HZD-ANA particles were synthesized from coal fly ash cenospheres composed of aluminosilicate glass with (SiO2/Al2O3)wt.=3.1 and characterized by PXRD, SEM-EDS, STA, and low-temperature N2 adsorption. The non-radioactive simulant solutions of different acidity (pH=2–10) and Cs+/Sr2+ content (0.5–50.0 mg/L) were used in the work. The effect of synthesis conditions on the HZD-ANA particle size, zirconia content and localization as well as the sorption behavior with respect to Cs+ and Sr2+ (capacity, KD) were clarified. It was found that the small-sized HZD-ANA composites surpasses the Zr free analcime and large-sized HZD-ANA material in the Cs+ and Sr2+ sorption parameters (KD ~104–106 mL/g). The conditions to synthesize the zirconia-analcime composite of the highly enhanced sorption ability with respect to Sr2+ (KD ~106 mL/g) were determined. The high-temperature solid-phase re-crystallization of Cs+/Sr2+-exchanged HZD-ANA composites was shown to occur at 1000 °C resulting in a polyphase system based on nepheline, tetragonal ZrO2, and glass phase.

Spectral Ellipsometry as a Method of Investigation of Influence of Rapid Thermal Processing of Silicon Wafers on their Optical Characteristics

One of the possible ways of improvement of the surface properties of silicon is the solid phase recrystallization of the surface silicon layer after the chemical-mechanical polishing with application of the rapid thermal treatment with the pulses of second duration. The purpose of the given paper is investigation of influence of the rapid thermal treatment of the initial silicon wafers of the various doping level and reticular density on their optical characteristics by means of the spectral ellipsometry method.The investigation results are presented by means of the spectral ellipsometry method of the rapid thermal processing influence on the initial silicon wafers (KDB12 orientation <100>, KDB10 orientation <111> and KDB0.005 orientation <100>) of the various level of doping and reticular density influence on their optical characteristics: refraction and absorption ratios. Influence was confirmed of the silicon reticular density on its optical characteristics before and after the rapid thermal processing. It was shown, that reduction of the refraction and absorption ratios in the center of the Brillouin zone for the silicon samples with the high Boron concentration after the rapid thermal processing as compared with the low doped silicon. In the area of the maximum absorption peak, corresponding to the energy of the electron exit from the silicon surface (4.34 eV) the refraction indicator of the high doped silicon becomes higher, than of the low doped silicon, which is determined by the high concentration of the vacant charge carriers on the silicon surface in this spectral range.It was established, that the spectral area 3.59–4.67 eV, corresponding to the work of the electrons, exiting the silicon surface, the most informative way shows the difference of the 3 optical parameters of silicon of the different orientation, and for evaluation of influence of the silicon doping level on its optical characteristics the most informative is the spectral range of 3.32–4.34 eV.

Solid Phase Recrystallization in Arsenic Ion-Implanted Silicon-On-Insulator by Microsecond UV Laser Annealing

UV laser annealing (UV-LA) enables surface-localized high-temperature thermal processing to form abrupt junctions in emerging monolithically stacked devices, where the applicable thermal budget is restricted. In this work, UV-LA is performed to regrow a silicon-on-insulator wafer partially amorphized by arsenic ion implantation as well as to activate the dopants. In a microsecond scale ( 10^-6 s to 10^-5 s) UV-LA process, monocrystalline solid phase recrystallization and dopant activation without junction deepening are evidenced, thus opening various applications in low thermal budget integration flows. However, some concerns remain. First, the surface morphology is degraded after the regrowth, possibly because of the non-perfect uniformity of the used laser beam and/or the formation of defects near the surface involving the excess dopants. Second, many of the dopants are inactive and seem to form deep levels in the Si band gap, suggesting a further optimization of the ion implantation condition to manage the initial crystal damage and the heating profile to better accommodate the dopants into the substitutional sites.

Bead-milling and recrystallization from natural marmatite to Fe-doping ZnS-C materials for lithium-ion battery anodes

The use of ZnS as anode materials in lithium-ion batteries (LIBs) has exhibited particular advantages of high theoretical capacity (962.3 mAh•g−1) and low discharge platform. Compared to chemosynthetic ZnS, natural marmatite (Fe-doped ZnS) can be regarded as a promising anode material with higher conductivity and lower cost. In this work, Fe-doped ZnS composites-1/2/3 (FZC-1/2/3) were synthesized by three methods: bead-milling, bead-milling with Super P, and solid-phase recrystallization (SPR) after bead-milling with Super P, respectively. FZC-3 exhibited high initial discharge and charge capacities of 1031.2 and 825.6 mAh g−1, respectively. Even after 200 cycles, it retained a charge capacity of 672.0 mAh g−1 at 0.2 A g−1, with a coulombic efficiency (CE) of 99.6%. Even at high specific currents of 2.0 and 10.0 A g−1, the maintained discharge capacities of 555.1 and 183.2 mAh g−1 after 1000 cycles, respectively, and the CE was almost 100%. In addition, phase transition of Fe and aggregation structure were characterized to explore the improvement of cycling stability. Furthermore, the first-principles calculation was performed to investigate Fe-doped ZnS and S-doped carbon. This work will provide a simple and practical method to produce marmatite-based anodes for LIBs.

Solid phase recrystallization induced by multi-pulse nanosecond laser annealing

The solid phase recrystallization of partially amorphized SOI structures using a pulsed Ultra-Violet Nanosecond Laser Annealing (UV-NLA) is reported. It is shown that combining UV-NLA process with a heating chuck at low temperature (450 °C) results in the perfect recrystallization of the amorphized portion of the silicon layer. Actually, sub-melt multi-pulse UV-NLA enables obtaining the total crystal recovery and a very high dopant activation rate, comparable to melt laser annealing approaches or high temperature rapid thermal annealing, with a very low overall thermal budget. This approach is a great alternative to traditional solid phase epitaxial regrowth process, which reach it limits, in terms of recrystallization rate, at temperatures lower than 500 °C. The process presented here is thus suitable for integration paths in which the thermal budget must be limited as for example 3D sequential integration. Besides the high activation rate, another benefit of the solid phase recrystallization, compared to an equivalent laser anneal in the melt regime, is the almost unchanged surface roughness. Furthermore, the use of an in-situ metrology based on Time Resolved Reflectometry (TRR) enables the monitoring of the crystalline seed thickness evolution during UV-NLA and the estimation of the recrystallization rate.

Formation of Nanocrystalline Silicon in Tin-Doped Amorphous Silicon Films

The process of crystalline silicon phase formation in tin-doped amorphous silicon (a-SiSn) films has been studied. The inclusions of metallic tin are shown to play a key role in the crystallization of researched a-SiSn specimens with Sn contents of 1–10 at% at temperatures of 300–500 ∘C. The crystallization process can conditionally be divided into two stages. At the first stage, the formation of metallic tin inclusions occurs in the bulk of as-precipitated films owing to the diffusion of tin atoms in the amorphous silicon matrix. At the second stage, the formation of the nanocrystalline phase of silicon occurs as a result of the motion of silicon atoms from the amorphous phase to the crystalline one through the formed metallic tin inclusions. The presence of the latter ensures the formation of silicon crystallites at a much lower temperature than the solid-phase recrystallization temperature (about 750 ∘C). A possibility for a relation to exist between the sizes of growing silicon nanocrystallites and metallic tin inclusions favoring the formation of nanocrystallites has been analyzed.

Effect of Solid-State Epitaxial Recrystallization on Defect Density in Ultrathin Silicon-on-Sapphire Layers

The main technological problem in the manufacture of electronics on silicon-on-sapphire (SOS) structures is the high density of defects in silicon-on-sapphire layers. The modern method of obtaining ultrathin SOS structures using solid-phase epitaxial recrystallization and pyrogenic thinning can significantly reduce the defectiveness in these layers. Nevertheless, the effect of the defectiveness of submicron SOS layers on the structural perfection of ultrathin layers remains unclear. In this work, ultrathin (100 nm) SOS structures have been obtained on submicron (300 nm) SOS structures with different structural quality. The crystallinity of 300 nm layers before the recrystallization process and ultrathin layers has been determined using X-ray diffraction and transmission electron microscopy. It has been found that the lowest values of the full width at half maximum (FWHM) of 0.19°–0.20° have been observed for an ultrathin SOS structure obtained based on the most structurally perfect SOS layers of 300 nm. It has been shown that a more perfect near-surface layer of the basic SOS structure of 300 nm and a double implantation regime make it possible to reduce the density of structural defects in the ultrathin Si layer by an order of magnitude to achieve ~1 × 104 cm–1.

An Optical Diffraction Method for Controlling the Solid-Phase Recrystallization and Heating of Implanted Semiconductors during Pulse Light Annealing

t—The results of the improvement of the method of laser diagnostics for investigating the heating dynamics, solid-state recrystallization, and melting of implanted semiconductors directly during a pulse light annealing procedure are presented. This technique is based on recording Fraunhofer diffraction patterns from special periodic structures; it allows investigations of structural–phase transitions in ion-doped semiconductor layers simultaneously with sample temperature measurements with a high time resolution. For this purpose, two measuring diffraction gratings were preliminarily formed on the surface of a silicon wafer: a phase grating and an amplitude grating. The solid-phase recrystallization and melting processes were studied via the kinetics of the disappearance and appearance of the diffraction maxima from the amplitude grating. The sample temperature was monitored by the deflection of the diffraction angle of the probe laser beam from the phase diffraction grating. This deflection is caused by a change in the grating period due to its thermal expansion.

SOLID PHASE RECRYSTALLIZATION OF A MECHANICALLY DISRUPTED SILICON LAYER SUBJECTED TO RAPID THERMAL TREATMENT

Quality and reliability of integrated circuits to a great extent depend on the surface condition of silicon wafers. In view of this, great attention is paid on the aspects of their preparation prior to their formation. It is of significant interest to study the possibility of applying rapid thermal treatment for solid phase re-crystallization of a mechanically disrupted layer of the wafer working side. The objective of this work was to establish the behavior regularities of a mechanically disrupted layer subjected to rapid thermal treatment with 2 s light pulses. As samples, there were used the silicon wafers with a diameter of 100 mm, grade KDB 12 and KEF 4.5, orientation <100> after chemical-mechanical polishing subjected to rapid thermal treatment during 7 s, which ensured their heating up to 1100 °C and without treatment. The application of the methods of Auger-spectroscopy, spectral ellipsometry, X-ray diffraction made it possible to state that such treatment increases the structural flawlessness of the surface layer of silicon wafers due to a decrease in the mechanically disrupted layer, thus ensuring obtaining the atomic-flat surface.

CMOS‐Compatible Controlled Hyperdoping of Silicon Nanowires

AbstractHyperdoping consists of the intentional introduction of deep‐level dopants into a semiconductor in excess of equilibrium concentrations. This causes a broadening of dopant energy levels into an intermediate band between the valence and the conduction bands. Recently, bulk Si hyperdoped with chalcogens or transition metals is demonstrated to be an appropriate intermediate‐band material for Si‐based short‐wavelength infrared photodetectors. Intermediate‐band nanowires can potentially be used instead of bulk materials to overcome the Shockley–Queisser limit and to improve efficiency in solar cells, but fundamental scientific questions in hyperdoping Si nanowires require experimental verification. The development of a method for obtaining controlled hyperdoping levels at the nanoscale concomitant with the electrical activation of dopants is, therefore, vital to understanding these issues. Here, this paper shows a complementary metal‐oxide‐semiconductor (CMOS)‐compatible technique based on nonequilibrium processing for the controlled doping of Si at the nanoscale with dopant concentrations several orders of magnitude greater than the equilibrium solid solubility. Through the nanoscale spatially controlled implantation of dopants, and a bottom‐up template‐assisted solid phase recrystallization of the nanowires with the use of millisecond‐flash lamp annealing, Se‐hyperdoped Si/SiO2 core/shell nanowires are formed that have a room‐temperature sub‐bandgap optoelectronic photoresponse when configured as a photoconductor device.

Microstructure Evolution of Si Nanocrystals in Si/C Multilayer Films

Si/C multilayer films deposited by radio frequency magnetron sputtering were post-annealed at 1100 °C for 1 h to produce Si nanocrystals (NCs). X-ray diffraction and Raman spectroscopy were used to analyze the phase composition and atomic vibration spectrum of the multilayer structure. High-resolution transmission electron microscopy was employed to verify the existence of Si NCs and to observe their sizes and morphologies. The results reveal that the Si NCs are formed by solid-phase recrystallization of the nanometer-thick layers of amorphous Si confined between C layers. The NC shape and size could be tuned by changing the modulation ratio of the Si layer and the C layer. When the ratio shifts from 0.5 to 2, the NCs become spherical, elliptical, square, or brick-shaped. This growth mode may be conducive to the design of different Si-based photo-electronic materials.

Application of ion implantation for the modification of silicon-on-sapphire epitaxial systems, their structure, and properties

Articles devoted to methods for improving the structural quality of epitaxial films, which utilize the high-temperature interaction between hydrogen and silicon as well as solid-phase recrystallization process, are reviewed. A correlation between the quality of the epitaxial layer and the radiation resistance of the microcircuits obtained thereon is also considered. A method for creating capture/recombination centers in sapphire during the implantation of helium ions is proposed, yielding high-quality radiation-resistant silicon-on-sapphire films.

Growth of high optical quality zinc chalcogenides single crystals doped by Fe and Cr by the solid phase recrystallization technique at barothermal treatment

The method of growing of ZnS and ZnSe single crystals doped with chromium and iron using a combination of the solid phase recrystallization and diffusion doping during the high-temperature gas-static pressing has been implemented. The isostatic pressing up to 110MPa has made it possible to increase the process temperature up to 1300°C, increase the rate of grain growth and diffusion of Fe2+ and Cr2+ ions in zinc chalcogenides crystalline samples, reduce processing time to 25–150h. ZnS:Cr (Fe) and ZnSe:Cr (Fe) single crystals from several to tens mm in size with dopant concentrations of (1–5)×1019cm−3 for Cr2+ and (5–20)×1018cm−3 for Fe2+ and at the total impurity's content no more than 5×10−4wt% have been obtained. The lasers made from the crystals demonstrated 55% differential lasing efficiency for the absorbed power.

Growth of high optical quality zinc chalcogenides single crystals by solid phase recrystallization technique at barothermal treatment

The solid phase recrystallization (SPR) technique under a barothermal high-temperature gas-static pressing (HIP) treatment was implemented to the growth for ZnS and ZnSe single crystals. The application of 200MPa isostatic pressure allowed increasing the process temperature up to 1150–1300°C, which in turn has increased the rate of grain growth and reduced process duration to 8–52h. The impurity contents in ZnS and ZnSe single crystals did not exceed 10−4wt%. The obtained crystals demonstrated transmittance in the wide VIS-IR spectral range close to the theoretical, ranging in size from a few to tens mm, which allows their use in practical applications as a laser matrix.

Microstructural evolution of a recrystallized Fe-implanted InGaAsP/InP heterostructure

Through the recrystallization of an amorphous heterostructure, obtained by MeV Fe ion implantation, we are able to tailor a standard epitaxial semiconductor material, a small gap InGaAsP/InP alloy, for photoconductive terahertz optoelectronics. Here, we report on microstructural changes occurring in the material over a broad range of rapid thermal annealing temperatures, using X-ray diffraction line profile analysis and transmission electron microscopy. Results show a complete amorphous transition of the heterostructure after multiple-energy implantations done at 83 K. Upon thermal annealing, multiple structural layers develop via solid phase epitaxy and solid phase recrystallization. The photoconductive InGaAsP layer becomes polycrystalline and submicron grained, with high crystalline volume fraction and apparent ⟨110⟩ texture. Many grains are elongated and internally faulted, with high densities of planar faults occurring on closed-packed (111) planes. The X-ray diffraction line broadening is anisotropic and evolves with rapid thermal annealing temperatures. At 500 °C, the X-ray coherent domain size estimate of 10 nm is aligned reasonably with electron microscopy made in faulted areas. Above 500 °C, a significant decrease of the planar fault density is detected. We discuss the influence of these microstructural changes happening with recrystallization temperatures on the ultrafast photoconductive response of Fe-implanted InGaAsP/InP.

Advanced Extra Functionality CMOS‐based Devices

AbstractThis volume contains the proceedings of the E‐MRS 2013 symposium K, entitled “Physics and Technology of Advanced Extra Functionality CMOS‐based Devices” that was held from May 27th to May 31st 2013 in Strasbourg, France. In total, 93 papers were presented, including 13 invited presentations, 51 contributed oral presentations and 29 poster presentations.Our symposium provided an open forum for the presentation of original experimental and theoretical studies that contribute to the physical understanding of phenomena related to new materials and processes for devices that add extra functionality to conventional CMOS backbone processes. Going from core CMOS technology to CMOS derivatives implies a change of paradigm in R & D. While core CMOS technology aims at improved performance, particularly switching speed, it is mandatory for CMOS derivatives to find a trade‐off between the traditional view of device ‘performance’ (switching speed,...) and increasingly critical low power consumption requirements (calling for improved control of leakage currents, standby power consumption, dark currents…).The high‐quality symposium contributions and the inspiring discussions in the various sessions all contributed to the symposium success, particularly thanks to the invited speakers who provided excellent reviews of their recent works and of the state‐of‐the‐art in their respective fields.The exciting opportunities and challenges associated to some specific More‐than‐Moore applications, such as CMOS imagers and healthcare applications were presented in the opening session by François Roy from STMicroelectronics and Sywert Brongers‐ma from Holst Centre/IMEC.Throughout the symposium, reviews of the main challenges related to most of the building blocks of advanced CMOS‐based devices were given in terms of both fundamental material studies and/or technology optimisation. These included substrate engineering (Eugene Fitzgerald, MIT), source/drain doping (Benjamin Colombeau, Applied Materials), dopant diffusion (Hartmut Bracht, Univ. Münster), source/drain silicide fabrication (Dominique Mangelinck, IM2NP‐CNRS) and high‐k gate stacks (Ramamurthy Ramprasad, Univ. of Connecticut).Physical modelling and simulation issues (from ab‐initio to continuum TCAD) were discussed during three dedicated sessions brightly introduced by Matthias Posselt from HZDR (solid phase recrystallization), Andreas Schenk from ETH Zurich (leakage current modelling) and Christoph Zechner from Synopsys (process technology simulations).Finally, recent advances in the field of 3D dopant/carrier characterisation were reported by Wilfried Vandervorst from IMEC, while the use of electrical characterisation to investigate the impact of source/drain defects on leakage currents and advanced MOSFET performances were discussed by Ray Duffy from Tyndall and Mireille Mouis from IMEP‐LAHC‐CNRS.These proceedings contain a selection of 48 manuscripts organised in 5 sections:– Doping and Thermal Processing: Basic Studies and Process Optimization– More‐than‐Moore and Advanced CMOS Devices– Atomistic Modelling and Continuum Simulations– Physical and Electrical Characterization– Silicides and Germanides.We would like to acknowledge the E‐MRS Headquarters staff for its outstanding assistance in organising the symposium as well as Wiley‐VCH staff for helping in the publication of these proceedings. We also wish to thank all contributors and attendees for their active participation to the symposium and all colleagues who reviewed the submitted manuscripts, and contributed in many cases to the improvement of the quality of the published articles.We also wish to congratulate the winners of the best student awards (Fabio Isa from L‐NESS Milano and Ruggero Milazzo from CNR‐IMM‐MATIS Padova) as well as the winners of the best poster awards (Thomas Kreiliger from ETH Zurich and Spyridon Stathopoulos from NTUA University Athens).Finally, the symposium organisers are grateful for the sponsorship provided by several companies and institutions (Ion Beam Services, Semilab, STMicroelectronics, Synopsys, and the CNRS), as well as for the support of the EU commission through the European Project ATEMOX (Advanced Technology Modelling for Extra‐Functionality Devices) that gave rise to the proposal for the organisation of this symposium. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Silicon ion implantation for growing structurally perfect silicon layers on sapphire

The paper presents the results of studying a method for improving the crystal structure of o silicon epitaxial layer on a sapphire substrate by its preliminary amorphization with high-energy silicon ions followed by its recovery (solid-phase recrystallization) to a structurally perfect single-crystal state. The structural and electrical parameters of silicon-on-sapphire compositions are comparatively analyzed before and after solid-phase recrystallization.

Characterization of ultrathin InSb nanocrystals film deposited on SiO2/Si substrate

Recently, solid-phase recrystallization of ultrathin indium antimonide nanocrystals (InSb NCs (films grown on SiO2/Si substrate is very attractive, because of the rapid development of thermal annealing technique. In this study, the recrystallization behavior of 35 nm indium antimonide film was studied. Through X-ray diffraction (XRD) analysis, it is demonstrated that the InSb film is composed of nanocrystals after high temperature rapid thermal annealing. Scanning electron microscopy shows that the film has a smooth surface and is composed of tightly packed spherical grains, the average grain size is about 12.3 nm according to XRD results. The optical bandgap of the InSb NCs film analyzed by Fourier Transform infrared spectroscopy measurement is around 0.26 eV. According to the current-voltage characteristics of the InSb NCs/SiO2/p-Si heterojunction, the film has the rectifying behavior and the turn-on voltage value is near 1 V.