The dielectric function of bi-axially strained, intrinsic, and pseudomorphic Si1−xGex alloys was measured at room temperature using spectroscopic ellipsometry from 0.74 eV to 5.06 eV. Un-doped Si1−xGex with germanium compositions ranging from 0 to 75% was grown on Si (001) using chemical vapor deposition. High resolution x-ray diffraction was used to confirm sample composition, thickness, and strain. X-ray relaxation scans showed that all the samples were fully strained. All the alloy films in this study have low values of surface roughness, which allowed determination of the dielectric function. The presence of strain in the Si1−xGex alloys clearly altered the dielectric response. The bi-axial stress induced shift of the E1 and El + Δ1 critical point energies of pseudomorphic alloys can be described by the elastic response to the strain based on k*p theory [Lange et al., J. Appl. Phys. 80, 4578 (1996)]. Although the critical point energies of the alloys having higher germanium concentration showed deviations from the large shear approximation, the strain induced shift in critical point energy and the relative intensities of E1 and El + Δ1 were reasonably well described by the full elastic theory.

A multi-technique approach was used to determine the crystalline phase, texture, and electronic structure of Hf1−xZrxO2 (x = 0–1) high-k gate dielectric thin films grown by atomic layer deposition using a cyclical deposition and annealing method. X-ray diffraction (XRD) analysis performed in both grazing incidence and pole figure configurations identified the tetragonal phase for Zr/(Zr + Hf)% = 58% and a concomitant increase in tetragonal phase for further increase in Zr content. X-ray absorption spectroscopy (XAS) was used to determine the local atomic structure and metal oxide bond orientation. Polarization dependent XAS in normal and grazing incidence showed preferential metal-oxygen bond orientation consistent with the texturing observed by XRD. X-ray photoemission spectroscopy (XPS) and spectroscopic ellipsometry (SE) were also performed with special focus on spectral features which arise as a consequence of atomic ordering and specific crystalline phase. The combination of XAS, XPS, SE, and XRD enabled the determination of the effects of the deposition scheme and compositional alloying on the electronic structure, crystal field effects, optical properties, crystal phase, and texture for the mixed oxide alloy series. The multi-technique approach revealed the martensitic-like transformation of crystalline phase from monoclinic to tetragonal as the majority metal oxide concentration in the alloy mixture changed from HfO2 to ZrO2.

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Abstract. Measurement and control of line edge roughness (LER) is one of the most challenging issues facing patterning technology. As the critical dimensions (CDs) of patterned structures decrease, an LER of only a few nanometers negatively impacts device performance. Here, Mueller matrix (MM) spectroscopic ellipsometrybased scatterometry is used to characterize LER in periodic line-space structures in 28-nm pitch Si fin samples fabricated by directed self-assembly patterning. The optical response of the MM elements is influenced by structural parameters like pitch, CDs, height, and side-wall angle, as well as the optical properties of the materials. Evaluation and decoupling MM element response to LER from other structural parameters requires sensitivity analysis using scatterometry models that include LER. Here, an approach is developed that can be used to characterize LER in Si fins by comparing the optical responses generated by systematically varying the grating shape and measurement conditions. Finally, the validity of this approach is established by comparing the results obtained from power spectral density analysis of top down scanning electron microscope images and crosssectional transmission electron microscope image of the 28-nm pitch Si fins. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

Characterization of the periodicity and strain state of an array of lithographically patterned silicon and silicon-germanium alloy on silicon fins using reciprocal space mapping of Bragg diffraction peaks is presented. Various patterned structures with different pitch values of 90 nm, 65 nm, and 42 nm have been studied and data for the 42 nm pitch sample is discussed in this paper. Diffraction from fin arrays is treated kinematically analogous to periodic surface grating structures. Diffraction from the symmetric 004 planes is used to calculate pitch and analyze the pitch walking pattern which appears as harmonic peaks on either side of the fin peaks. Pitch walking refers to the presence of two periodicities in the array due to the lithographic process. Longitudinal scans are evaluated at the fin peak positions to probe into the shape of the fin structure. Nonrectangular fin shapes resulted in peak splitting of the longitudinal scans of higher order fin peaks indicating a finite sidewall slope. Asymmetric 224 planes were analyzed to study the quality and strain-relaxation of the fin structures both parallel and perpendicular to the fin length using reciprocal space mapping techniques.