Study of thin-film thickness and density by high-resolution Rutherford backscattering spectrometry and X-ray reflectivity

Kitahara, Amane; Yasuno, Shinji; Fujikawa, Kazuhisa

doi:10.14723/tmrsj.34.613

Cited by 10 publications

(8 citation statements)

References 4 publications

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“…17) HR-RBS measurements were carried out using 450 keV He + ions, which were irradiated at an incident angle of 32°onto the films using a high-stability Cockcroft-Walton-type high-voltage generator, and the scattered He + ions were detected at a scattering angle of 77°using a high-resolution energy analyzer. 16) The beam size ranges from 0.5 × 0.5 to 1.0 × 1.0 mm 2 . For ERDA, the films were irradiated with a collimated beam of 450 keV N + ions at an incident angle of 70°.…”

Section: Experimental Methodsmentioning

confidence: 99%

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Electrical and physical characterizations of the effects of oxynitridation and wet oxidation at the interface of SiO₂/4H-SiC(0001) and

Shiomi

Kitai

Tsujimura

et al. 2016

Jpn. J. Appl. Phys.

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The effects of oxynitridation and wet oxidation at the interface of SiO2/4H-SiC(0001) and were investigated using both electrical and physical characterization methods. Hall measurements and split capacitance–voltage (C–V) measurements revealed that the difference in field-effect mobility between wet oxide and dry oxynitride interfaces was mainly attributed to the ratio of the mobile electron density to the total induced electron density. The surface states close to the conduction band edge causing a significant trapping of inversion carriers were also evaluated. High-resolution Rutherford backscattering spectroscopy (HR-RBS) analysis and high-resolution elastic recoil detection analysis (HR-ERDA) were employed to show the nanometer-scale compositional profile of the SiC-MOS interfaces for the first time. These analyses, together with cathode luminescence (CL) spectroscopy and transmission electron microscopy (TEM), suggested that the deviations of stoichiometry and roughness at the interface defined the effects of oxynitridation and wet oxidation at the interface of SiO2/4H-SiC(0001) and .

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Section: Experimental Methodsmentioning

confidence: 99%

“…15) In terms of physical measurements, we focused on the highresolution Rutherford backscattering spectroscopy (HR-RBS) analysis and high-resolution elastic recoil detection analysis (HR-ERDA), in order to analyze the nanometer-scale compositional profiles of the SiO 2 =SiC interfaces. 16,17)…”

Section: Introductionmentioning

confidence: 99%

Electrical and physical characterizations of the effects of oxynitridation and wet oxidation at the interface of SiO₂/4H-SiC(0001) and

Shiomi

Kitai

Tsujimura

et al. 2016

Jpn. J. Appl. Phys.

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“…In literature, often these techniques yield different results for the same film [37,38]. For instance, the thickness of HfO 2 film was determined to be 0.21 nm from RBS, whereas XRR showed the thickness to be 1.2 nm [37]. However, it is believed that XRR can be considered to evaluate the thickness more precisely when compared to the RBS technique due to its high-density contrast [37].…”

Section: The Xrd Patterns Of Thementioning

confidence: 99%

Role of Ni substitution on structural, magnetic and electronic properties of epitaxial CoCr₂O₄ spinel thin films

Mohanty¹,

Chowdhury²,

Choudhary³

et al. 2020

Nanotechnology

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Cubic spinel CoCr 2 O 4 has attained recent attention due to its multiferroic properties. However, the Co site substitution effect on the structural and magnetic properties has rarely been studied in thin film form. In this work, the structural and magnetic properties of Co 1x Ni x Cr 2 O 4 (x = 0, 0.5) epitaxial thin films deposited on MgAl 2 O 4 (100) and MgO (100) substrates to manipulate the nature of strain in the films using pulsed laser deposition (PLD) technique are presented. The epitaxial nature of the films was confirmed through X-ray diffraction (XRD) and Rutherford backscattering spectrometry (RBS) measurements. Raman measurements revealed a disappearance of characteristic A 1g and F 2g modes of the CoCr 2 O 4 with increase in the Ni content. Atomic force microscopy (AFM) studies show a modification of the surface morphology upon Ni substitution. Magnetic measurements disclose that the ferrimagnetic Curie temperature (T c ) of the CoCr 2 O 4 in thin film grown on MgAl 2 O 4 (100) and MgO (100) substrates were found to be 100.6 ± 0.5 K and 93.8 ± 0.2 K, respectively. With Ni substitution the transition temperatures significantly get enhanced from that of CoCr 2 O 4 . X-ray photoelectron spectroscopy (XPS) suggests Cr 3+ oxidation states in the films, while Co ions are present in a mixed Co 2+ /Co 3+ oxidation state. The substitution of Ni at Co site significantly modifies the line shape of the core level as well as the valence band. Ni ions are also found to be in a mixed 2+/3+ oxidation state. O 1s core level display asymmetry related to possible defects like oxygen vacancies in the films. CoCr 2 O 4 is a ferrimagnetic spinel compound with complex magnetic interactions at low temperatures [1]. The magnetic cations Co 2+ and Cr 3+ ions occupy the tetrahedral A and octahedral B sites, respectively, of the spinel structure [1]. Below Curie temperature (T C = 93 K), a collinear ferrimagnetic ordering occurs, with further lowering the temperature to 26 K (T S ) the compound develops a short-range-ordered (SRO) spiral component [1]. Theoretical calculations has also evidenced the T S feature due to the nesting of the Fermi surface having high degree of magnetic instability in the system associated with the nesting vector q along the [110] direction [2]. Recent experiments have shown the size dependence of these magnetic transitions [3]. Below a critical particle size of d c , spiral = 4.4 (1) nm, the spiral ordering vanishes [3] and for size less than d c , col = 3.3 (1) nm, the collinear magnetic order disappears [3]. A lock-in transition at a temperature T L = 15 K appears because of the incommensurate-to-commensurate magnetic phase transition [1]. At T L the period of the spin spiral eventually "locks in" to the lattice parameter [1]. This spiral component is responsible for inducing the multiferroicity in CoCr 2 O 4 [1]. Structurally, CoCr 2 O 4 is stable and remains cubic with space group Fd ̅ m at all temperatures as the sample is cooled down to 10 K [4].On the other hand for NiCr 2 O 4 the crystal ...

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“…Figure 1(b) shows the hafnium (Hf) peaks of all the films of different thickness. The width of the peaks indicates the relative thickness [36,37]. The density (ρ) of the thin films could be obtained by measuring the areal atomic density (N S ) by RBS spectrometry and the film thickness (t) independently [37][38][39].…”

Section: Compositional Propertiesmentioning

confidence: 99%

Optimization and integration of ultrathin e-beam grown HfO₂ gate dielectrics in MoS₂ transistors

Ganapathi¹,

Bhat²,

Mohan³

2021

J. Phys. D: Appl. Phys.

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Integration of high-k dielectrics with two-dimensional (2D) layered semiconductors is one of the bottleneck in realization of the devices in a viable technology. In this work we report on the optimization and integration of electron beam (e-beam) evaporated, ultrathin (5 nm) HfO2 thin films on a few layer (5–7 nm) MoS2 substrate, without the need for any functionalization and buffer layers. The effect of HfO2 film thickness on optical, compositional and electrical properties of the material has been evaluated using ellipsometry, Rutherford backscattering, x-ray photoelectron spectroscopy and electrical measurements. The estimated dielectric constant and leakage current density values have been correlated with the refractive index and density of the films. It has been observed that the dielectric constant decreased drastically in ultrathin (5 nm) HfO2 film in case of Al as a gate electrode due to the formation of interfacial layer. The effect of gate electrode material and its processing on dielectric properties of ultra-thin films has been studied in detail and it is found that e-beam evaporated Ni seems to be a promising gate electrode. Equivalent oxide thickness of 1.2 nm and leakage current density (J) of 1.1 × 10−4 A cm−2 have been achieved for 5 nm films with Ni as gate electrode. Top gated MoS2 transistors with, 5 nm HfO2 gate dielectric show very good performance with I ON to I OFF ratio of 106. We thus demonstrate e-beam evaporation as a promising technique to directly integrate high-k dielectrics (HfO2) with 2D materials.

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Study of thin-film thickness and density by high-resolution Rutherford backscattering spectrometry and X-ray reflectivity

Cited by 10 publications

References 4 publications

Electrical and physical characterizations of the effects of oxynitridation and wet oxidation at the interface of SiO₂/4H-SiC(0001) and

Electrical and physical characterizations of the effects of oxynitridation and wet oxidation at the interface of SiO₂/4H-SiC(0001) and

Role of Ni substitution on structural, magnetic and electronic properties of epitaxial CoCr₂O₄ spinel thin films

Optimization and integration of ultrathin e-beam grown HfO₂ gate dielectrics in MoS₂ transistors

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Study of thin-film thickness and density by high-resolution Rutherford backscattering spectrometry and X-ray reflectivity

Cited by 10 publications

References 4 publications

Electrical and physical characterizations of the effects of oxynitridation and wet oxidation at the interface of SiO2/4H-SiC(0001) and

Electrical and physical characterizations of the effects of oxynitridation and wet oxidation at the interface of SiO2/4H-SiC(0001) and

Role of Ni substitution on structural, magnetic and electronic properties of epitaxial CoCr2O4 spinel thin films

Optimization and integration of ultrathin e-beam grown HfO2 gate dielectrics in MoS2 transistors

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Electrical and physical characterizations of the effects of oxynitridation and wet oxidation at the interface of SiO₂/4H-SiC(0001) and

Electrical and physical characterizations of the effects of oxynitridation and wet oxidation at the interface of SiO₂/4H-SiC(0001) and

Role of Ni substitution on structural, magnetic and electronic properties of epitaxial CoCr₂O₄ spinel thin films

Optimization and integration of ultrathin e-beam grown HfO₂ gate dielectrics in MoS₂ transistors