Latest innovations in high brightness X-ray sources, more efficient Xray detectors combined to the intrinsic capability of X-rays to probe materials at sub nanometer scale are opening new opportunities for the characterization of new materials and structures like FINFETs at the advanced technology nodes. The metrology challenges at 22 nm node and below (ie, shrinking size, thinner films, introduction of new material and 3 D structures) will also results in the development of a new generation of metrology tools and methods for process control. Moreover the transition to 450 mm wafer manufacturing will add challenges related to throughput. As stated by G450C in Albany, the throughput at 450mm for a given metrology has to match the equivalent one at 300mm. For X-ray metrology this requirement will translates in brighter X-ray sources, more efficient optics and detectors in order to speed up the measurements and meet the specifications. In this paper we will discuss new high brightness X-ray sources and the most important applications for X-ray metrology for the next five years.

This study investigates the application of inline high resolution x-ray diffraction (HRXRD) for process control of Si/SiGe and conventional Si on silicon-on-insulator (SOI) fin-shaped field effect transistors (FinFETs). HRXRD measurements were taken from test pads on production wafers; the process stages under study were pre- and post-fin etch. For the pre-etch stage, HRXRD monitors the Si or Si/Ge thickness, Ge concentration (%), and crystal quality. For thickness, HRXRD results matched the fin height from a corresponding device within 2 Å. When equipped with a 1D detector, the typical measurement time can be as short as 20 min. In the post-etch stage, HRXRD monitors fin pitch with a precision of 3 nm. The choice of diffraction plane has an impact on the signal-to-noise ratio. In particular, the asymmetric 113 reciprocal space map (RSM) has better signal-to-noise than 004 for monitoring Si fins; however, pitch data obtained from these two diffraction planes matches within the measurement precision. The etch process can induce relaxation along the fin height in the Si/SiGe hetero-epitaxial fin and has a deleterious impact on the device’s drive current. Although the RSM is sensitive to such relaxation, a nanobeam diffraction measurement is still needed for quantitative strain measurements. The results show inline HRXRD is a valuable tool for monitoring pre- and post-etch processes during FinFET production. It can track vital fin parameters, including fin height, pitch, and crystal quality, which determine the final device drive current. The measurement is nondestructive and can be taken directly from testing pads in production wafers; it therefore saves testing cost and time and alleviates reliance on destructive techniques like transmission electron microscopy.

An In0.25Ga0.75Sb/InAs strained-layer superlattice, grown by molecular-beam epitaxy (MBE) on a GaSb[001] substrate, has been characterized by four-circle x-ray diffractometry. This system, proposed by Maliot and Smith for ir detection application, is challenging because of the two group V species and the likelihood of cross-incorporation of the different elements during growth, leading possibly to interdiffusion and thus, to a more diffuse interface. High-resolution x-ray diffraction (XRD) profiles were obtained about several reciprocal lattice points in order to extract a reliable set of structural parameters. The profiles were then successfully modeled by computer simulation. The presence of many sharp higher-order satellite reflections in the XRD profiles is a measure of the high quality of the superlattices. The normal and lateral structural coherence was also measured and will be discussed.

Nanometer thick films, quantum dots, and quantum wires are the basis of the modern electronic industry. X-ray diffraction techniques play an increasingly important role as basic characterization tools for determining detailed structural information of ultrathin film such as the evolution of strain relaxation, defect formation, film/substrate interfacial properties, and the effects of the reduced dimensionality and structural correlations to electrical properties. Materials of technological interest are SiGe and strained Si; artificial substrates such as silicon on insulator; high- and low-κ dielectric materials, which will substitute SiO2; materials for interconnects; new materials for memory storage; micro-electro-mechanical systems (MEMS); and photovaltaics. An overview of the major X-ray scattering applications of interest to this industry will be presented in this article.

Thin epitaxial films of TbBaCo2O6-delta cobaltites have been synthesized using pulsed laser deposition. It was found that the film properties are extremely sensitive to the oxygen pressure during deposition, temperature of the substrate, and the cooling rate. Growth parameters were optimized for (delta approximate to 0.5 films with ordered Tb and Ba ions, as well as oxygen vacancies. The properties of these c-axis oriented films are similar to bulk TbBaCo2O5.5: they show a metal-insulator phase transition at T-MI approximate to 350 K, ferromagnetic order below T-C=285 K, and antiferromagnetism at T<T-i approximate to 230 K.

We present an extended synchrotron x-ray scattering study of the structure of thin manganite films grown on SrTiO3(001) substrates and reveal a new kind of misfit strain relaxation process which exploits twinning to adjust lattice mismatch. We show that this relaxation mechanism emerges in thin films as one-dimensional twinning waves which freeze out into a twin domain pattern as the manganite film continues to grow. A quantitative microscopic model which uses a matrix formalism is able to reproduce all x-ray features and provides a detailed insight into this novel relaxation mechanism. We further demonstrate how this twin angle pattern affects the transport properties in these functional films.

Biaxially strain is an important parameter in the complex phase diagram of the doped manganites that can lead to a different groundstate compared to bulk single crystals at the same doping level. For coherently strained La2/3Ca1/3MnO3 thin films on SrTiO3 substrates, we report an unusual direction dependence of the electrical transport properties. For transport perpendicular to the substrate induced strained plane, an insulating behavior associated with non-linear current–voltage characteristics is observed. We propose an A-type antiferromagnetic groundstate for the biaxially strained films as is consistent with the observed strongly reduced saturation magnetization.

Due to the complex interplay of magnetic, structural, electronic, and orbital degrees of freedom, biaxial strain is known to play an essential role in the doped manganites. For coherently strained La2/3Ca1/3MnO3 thin films grown on SrTiO3 substrates, we measured the magnetotransport properties both parallel and perpendicular to the substrate and found an anomaly of the electrical transport properties. Whereas metallic behavior is found within the plane of biaxial strain, for transport perpendicular to this plane an insulating behavior and nonlinear current-voltage characteristics (IVCs) are observed. The most natural explanation of this anisotropy is a strain induced transition from an orbitally disordered ferromagnetic state to an orbitally ordered state associated with antiferromagnetic stacking of ferromagnetic manganese oxide planes.

The magnetism of a DHCP Ho–Ce alloy has been investigated using X-ray magnetic resonant scattering. A self-consistent magnetic structure is proposed that agrees with diffraction data for three different cross sections (neutron, dipolar and quadrupolar). The spectroscopic valence of the Ce is found to be 3.27(5), and the Ce is in an intermediate-valence state in this alloy.

X-ray scattering experiments have demonstrated that for thin films (100 Å to 500 Å) of La0.9Sr0.1MnO3 epitaxially grown on SrTiO3 (100) substrates, the accommodation of the lattice mismatch between film and substrate gives rise to a modulated structure. The non-bulk-like structural properties of these thin films are the origin of anomalies in the electronic and magnetic behavior. Studies of the lattice as a function of temperature clearly reveal a magnetostrictive effect close to the Curie temperature. For thicker films the strain relief mechanism is replaced by formation of coherent microtwins and some of the bulk properties are recovered, but some differences are still observed.

We study the origin of the resonant x-ray signal in manganites and generalize the resonant cross section to the band-structure framework. With nb initio LSDA and LSDA + U calculations we determine the resonant x-ray spectrum of LaMnO3. The calculated spectrum and azimuthal angle dependence at the Mn K edge reproduce the measured data without adjustable parameters. The intensity of this signal is directly related to the orthorhombicity of the lattice. We also predict a resonant x-ray signal at the La L edge, caused by the tilting of the MnO6 octahedra. This shows that the resonant x-ray signal in the hard x-ray regime can be understood in terms of the band structure of a material and is sensitive to the fine details of crystal structure.

The magnetic ordering in HoxCe1-x alloys has been investigated by neutron diffraction and X-ray magnetic resonant scattering (XMRS). The DHCP alloys display a rich phase diagram, and highly unusual, diffuse neutron magnetic scattering is observed over the composition range 0.35 less than or equal to x less than or equal to 0.5. The diffuse intensity may be the magnetic response of the conduction band, and this interpretation is supported by the XMRS measurements, which show that there is hybridisation of the Ce 4f electron with the conduction electrons. (C) 2000 Elsevier science B.V. All rights reserved.

We are reporting an unexpected metal insulator transition at the ferromagnetic phase-transition temperature for thin films of La0.9Sr0.1MnO3 (<50 nm), grown on a (100) face of SrTiO3 substrate. For the thicker films (>50 nm), similar to the single crystal, no such transition is observed below TC. Additionally, we observe the suppression of the features associated with charge or orbital ordering in intentionally La-deficient thin films of La0.88Sr0.1MnO3 (<75 nm). In thin films, transmission electron microscopy reveals a compressive strain due to the epitaxial growth, that is, lattice parameters adopt those of the cubic lattice of SrTiO3. As the film thickness increases, coherent microtwinning is observed in the films and the films relax to a orthorhombic structure.

Single-crystal Nd/Pr superlattices have been studied using resonance-enhanced magnetic X-ray scattering. Magnetic resonances were observed at the LII edges of Nd and Pr, so it was possible to study the magnetism of both components of a superlattice separately for the first time using synchrotron X-rays. The results demonstrate that the 5d bands are magnetically polarised in both elements, and suggest that the induced ordering in the Pr is localised. The induced moment profile across the Pr blocks has been determined and the results correlated with the observed magnetic coherence of the Nd. Thus new insight is obtained on the nature of the induced ordering of the Pr and on the interlayer coupling mechanism.

The magnetic structures of Nd/Pr superlattices have been investigated using x-ray magnetic resonant scattering. Magnetic dipole resonances were observed at the edges of both components of the superlattices, proving that a coherent spin-density wave is established in the 5d bands of both elements. Multi- q magnetic structures were induced in the Pr, and the two components of the superlattice were found to adopt identical magnetic modulation vectors. Magnetic superlattice peaks were observed in Q-scans at both edges and from these we were able to determine the magnetization profiles in each component of the superlattice separately. From the width of the magnetic peaks in the wave-vector, , we were able to measure the magnetic coherence of the Nd, and the results demonstrate that the observed spin-density wave in the Pr is responsible for the coupling between successive Nd blocks.

We present a study of the structural and magnetic properties of single-crystalline EuB{sub 6}. Temperature-dependent x-ray diffraction found no significant anomalies at the onset of ferromagnetic order. The resistivity, dc susceptibility, magnetization, and specific heat prove the crystal to be of extraordinarily high quality. Two ferromagnetic transitions at T{sub c1}=15.3 K and T{sub c2}=12.5 K are observed in all investigated properties. The ordered state displays an unexpected anisotropy, and we derive the magnetic phase diagrams for the three principal cubic directions. We argue that the two magnetic phases are connected by spin reorientation, enabled by a reduction of the crystalline symmetry from cubic. An additional anomaly in the specific heat is observed at low temperatures, which we interpret as arising from the splitting of the Eu ground-state multiplet in internal magnetic fields. {copyright} {ital 1998} {ital The American Physical Society}

We have searched for spin-slip lockins with impurity layers introduced into Ho and Er as artificial superlattice perturbations. The locking interaction with the impurities appears to be weak or nonexistent.

Neutron and x-ray scattering measurements have been made of the magnetic phase transition in a thin single-crystal film of holmium. The 5000 Å film was grown on a seed of a lutetium and yttrium alloy with a concentration chosen such that the basal plane was lattice matched to the holmium film. It was capped by 10000 Å of a similar film. The measurements below gave the critical exponent . Above the scattering suggests that the anomalous long-length-scale scattering is at least 20 times weaker than has been observed in similar experiments on bulk and thin-film holmium. These results show that the long-length-scale scattering is associated with the crystallographic surface rather than the end of the magnetic layer. The implications of this result for the origin of this type of scattering are discussed.