Characterization of polycrystalline In(y)Al(x)Sb(1-x-y) films deposited by magnetron sputtering

Journal Pre-proof

Characterization of polycrystalline In(y) Al(x) Sb(1-x-y) films deposited by magnetron sputtering Charles A Bolzan , Danay J Manzo , Antonio Marcos H de Andrade , Julio ´ R Schoffen , Raquel Giulian PII: DOI: Reference:

S0040-6090(19)30657-1 https://doi.org/10.1016/j.tsf.2019.137630 TSF 137630

To appear in:

Thin Solid Films

Received date: Revised date: Accepted date:

6 April 2019 3 October 2019 10 October 2019

Please cite this article as: Charles A Bolzan , Danay J Manzo , Antonio Marcos H de Andrade , Julio ´ R Schoffen , Raquel Giulian , Characterization of polycrystalline In(y) Al(x) Sb(1-x-y) films deposited by magnetron sputtering, Thin Solid Films (2019), doi: https://doi.org/10.1016/j.tsf.2019.137630

This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 Published by Elsevier B.V.

Highlights:  Polycrystalline In(y)Al(x)Sb(1-x-y) films can be deposited by magnetron sputtering 

The Al at the surface of the films is mostly oxidized



No Al-Sb bonding at the surface of In(y)Al(x)Sb(1-x-y)films

1

Characterization of polycrystalline In(y)Al(x)Sb(1-x-y) films deposited by magnetron sputtering Charles A Bolzan1, Danay J Manzo 1, Antonio Marcos H de Andrade1, Júlio R Schoffen1, Raquel Giulian1* 1

Institute of Physics, UFRGS, Av. Bento Gonçalves 9500, Porto Alegre – RS, CEP 91501–970, Brazil. *

e-mail: [email protected]

Abstract. In(y)Al(x)Sb(1-x-y) films were deposited on SiO2/Si substrates by co-sputtering of InSb, Al and Sb targets and the electronic and structural properties of the films were investigated as a function of Al concentration (x). The elemental composition was probed by Rutherford backscattering spectrometry and particle induced x-ray emission analyses, whilst grazing incidence x-ray diffraction provided information about phase, structure and lattice parameters. Surface chemical composition was investigated by xray photoelectron spectroscopy. Here we demonstrate that films deposited at 420°C are polycrystalline, with zincblende phase. The lattice parameter of In(y)Al(x)Sb(1-x-y) films can be tuned by varying the Al concentration, in agreement with Vegard’s law. In addition, we show that the aluminum at the surface is mostly oxidized with no evidence of formation of Al-Sb bonding (at the surface), which comprises a mixture of In-Sb and indium and antimony oxide compounds.

2

Keywords: Antimonide; Thin films; Magnetron sputtering; Grazing incidence x-ray diffraction; X-ray photoelectron spectroscopy; Rutherford backscattering spectrometry; Particle induced x-ray emission analyses

1. Introduction The group III-V compounds are important semiconductor materials due to their potential applications as red diode lasers, infrared detectors and possible replacements for silicon as the channel material in the production of MOSFETs for low power/high performance applications [1–4]. InSb is a semiconductor with internal quantum efficiency close to 100 %, making it an important midwavelength (3–5 μm) infrared material for high performance detectors [5]. At a temperature of 300 K, the lattice constant of InSb is 6.479 Å, its bandgap is 0.17 eV (infrared region of the electromagnetic spectrum) and its electron mobility may reach 80,000 cm2/V ⋅ s, one of the largest among all semiconductors, with an electron mean free path approaching 1 μm [6]. On the other hand, AlSb possesses the highest bandgap amongst the antimonides (~1.63 eV (near-infrared)), with a lattice constant of 6.136 Å at room temperature. In recent years, it has found considerable use as the barrier material in high mobility electronic and long-wavelength optoelectronic devices [7,8]. Binary semiconductor compounds, when combined, may form ternary and even quaternary compounds, whose properties, in general, are intermediate between those of the two binary ones. For example, Al(y)Ga(x)As(1-x-y) and In(y)Ga(x)Sb(1-x-y) ternaries [9,10] can have their bandgap changed with stoichiometry, the relationship between lattice constant and composition following an almost linear trend, as predicted by Vegard’s law. For this reason, many of the ternary and quaternary semiconductor compounds are useful or potentially useful for the fabrication of high-performance infrared detectors. The In(y)Al(x)Sb(1-x-y) provides a convenient strain-compensating

3

barrier for mid-IR interband cascade lasers [11] and finds widespread application in the fabrication of specialized high-speed electronic and optical communication devices [12,13] and high luminous efficiency LEDs for gas sensors [14]. The growth of InAlSb films by molecular beam epitaxy (MBE) has been shown by many research groups [15,16] and may result in single crystalline films when suitable substrates with similar lattice parameters are used [17]. Atomic ordering in epitaxial semiconductor films leads to a reduction of the film structure from the original F-43m symmetry to a rhombohedral R3m symmetry, as observed in a large variety of III-V ternary and quaternary compound films grown on (001) oriented substrates. This has a strong impact on the optical and electronic properties of the film [18]. An alternative, very powerful technique regularly used for thin films fabrication is magnetron sputtering. It is a flexible technique that allows the deposition of highpurity films, as well as good control of film thickness and structure on a variety of substrates [19,20]. The characteristics of sputter-grown films strongly depend on the substrate, pressure, growing rate, deposition temperature, and other parameters [20]. Compared to MBE-grown films, the sputter-grown ones can be produced more quickly and cheaply; besides, they seldom exhibit single crystal structure. However, relatively little work has been reported on the fabrication of antimonide films by magnetron sputtering [21], in particular regarding InAlSb thin films [22]. Here we present a comprehensive structural and chemical characterization of non-epitaxial In(y)Al(x)Sb(1-x-y) films deposited on SiO2/Si substrates by magnetron sputtering. Grazing incidence x-ray diffraction (GIXRD) and Rutherford backscattering spectrometry (RBS) analyses were used to inspect the influence of Al concentration on the structural properties of the films. Surface chemical composition was probed by x-ray photoelectron spectroscopy (XPS), yielding information about oxidation states.

4

2. Experimental In(y)Al(x)Sb(1-x-y) films were deposited by magnetron sputtering on SiO2/Si substrates by co-sputtering from InSb, Al and Sb targets using an AJA International ATC Orion-8 Sputtering System. Films with different stoichiometries were prepared by varying the relative concentration of the In and Al, namely with 0%, 9%, 15% and 18% of the Al in the total atomic concentration of the films. The base pressure to deposition was below 5.3 × 10−6 Pa and during deposition it was kept at 2.7 × 10−2 Pa using a 20 sccm Ar constant flow and an adaptive pressure controller. The target diameter was 2 in and the target-substrate distance was 5.8 in (confocal configuration) with the substrate kept at 420°C while rotating at 40 rpm. The InSb film (x=0%) was deposited by sputtering of the InSb compound target only. For x=9%, 15% and 18%, Sb target was set to 15W (RF), 22W (RF), and 30W (RF), respectively. Al target was set to 15W(DC) , 40W(DC), and 65W(DC), in this order, for the In0.41Al0.09Sb0.5, In0.35Al0.15Sb0.5, and In0.32Al0.18Sb0.5 films. InSb target was set to 100 W (RF) for all Al concentrations. RBS measurements were performed using a Tandetron accelerator with 1-1.5 MeV He+ ions and interval currents from 10 to 20 nA. The Si surface barrier detector was used to detect backscattered particles, positioned at 15° with respect to the beam direction. Experimental data were simulated using the SIMNRA [23] code. The relative ratio between In, Al and Sb was measured with 2 MeV protons and mean current of 0.5 nA by means of the particle induced x-ray emission (PIXE) technique. The PIXE calibration was performed via the H method described elsewhere [24] and the corresponding spectrum was analyzed with the GUPIXWIN software package [25]. The

5

x-rays induced by the proton beam were detected using a Si(Li) detector with an energy resolution of 155 eV at 5.9 keV, positioned at 135° with respect to the beam direction. To that end, thin x-ray fluorescence calibration standard films were employed. GIXRD measurements were carried out in a Bruker D8 Advance diffractometer in 2 configuration using Cu K radiation (1.5418 Å). The angle between the incoming beam and samples surface was kept constant and equals to

, while the detector was

moved along the 2 circle from 20 to 65 with step size of 0.020 and acquisition time of 5s per step. XPS measurements were performed at the D04A-SXS beamline endstation [26] of the Brazilian Synchrotron Light Laboratory (LNLS). The samples were analyzed with no pre-treatment using the long scan, C 1s, In 3d, Sb 3d, Al 2p, and Al 1s scan regions. A InSb (111) double-crystal monochromator was used to collect the spectra at a fixed photon energy (hν) of 1840 eV. An energy step of 0.1 eV was set at the hemispherical electron analyzer (PHOIBOS HSA3500 150 R6), with energy pass of 40 eV or 20 eV (for the specific case of C 1s, In 3d, Al 2p, Al 1s and Sb 3d regions), with an acquisition time of 100 ms/point. The monochromator photon energy calibration was done at the Si K edge (1839 eV) and the base pressure inside the chamber was around 2.0 × 10−7 Pa. The analyzer’s energy was calibrated using a standard Au foil (Au 4f7/2 peak at 84.0 eV). The C 1s peak was considered to be at 285 eV and used as a reference to investigate possible charging eff ects. The XPS measurements were carried out at room temperature and a 45° takeoff angle. The XP spectra were analyzed with XPSPeak version 4.1 and all peaks were adjusted using an asymmetric Gaussian−Lorentzian sum function with 23% (1840 eV) Lorentzian contribution and a Shirley-type background.

3. Results and Discussion 6

3.1. Deposition parameters

As previously reported, antimonide binary compound films (GaSb, InSb and AlSb) can be successfully deposited by magnetron sputtering, with characteristics that vary according to deposition temperature and film thickness [21,27]. The formation of ternary compounds by magnetron sputtering including In(y)Ga(x)Sb(1-x-y) and In(y)Ga(x)As(1-x-y) thin films [28,29] has also been reported. However, the formation of stoichiometric ternary compounds by magnetron sputtering is not as straightforward as it is for their binary counterparts. Several attempts were required, varying the deposition parameters, to obtain In(y)Al(x)Sb(1-x-y) thin films with different Al concentrations and without In, Al or Sb excess, which are easily oxidized. The structure and composition of the films were measured by GIXRD, RBS and PIXE analyses and deposition parameters were adjusted to yield films with the desired stoichiometries. The best films were considered the ones with the least amount of oxygen, the largest crystallite sizes and free from unwanted metallic or oxide crystalline phases. Figure 1 shows GIXRD patterns of selected samples deposited at 420° C where small variations in the sputtering rates during deposition yielded films with unwanted metallic and oxide phases. Although the presence of the InAlSb compound can be noticed for all samples, its zincblende phase gives rise to a peak at a slightly different angle according to In and Al relative concentrations, as a consequence of the decrease in lattice distance with increasing Al content (details in the next subsection). A peak relative to the Sb2O3 orthorhombic phase appears at ~28 °, while peaks relative to the In tetragonal phase appear at 3 distinct angles, the most prominent one at ~ 33°. By reducing the power applied to the Al and Sb targets, the excess of both In and Sb2O3

7

decreases, as the Al:Sb power ratio (PAl/ PSb) decreases (table 1). The formation of the In0.32Al0.18Sb0.5 compound is effectively achieved for PAl/ PSb around 2.2 (figure 1 and table 1), in agreement with the phase equilibria of Al-In-Sb systems previously measured and calculated by Sharma et al. [30], which showed that, below 525.7 °C, the In(y)Al(x)Sb(1-x-y) phase is stable for 50% Sb. The formation of thin In(y)Al(x)Sb(1-x-y) films by magnetron sputtering with the intended stoichiometry may be particularly difficult due to the dissociation of III-V compounds in vacuum at temperatures below the melting point and to the substantial differences in the vapor pressures of their constituents at the melting point [22]. Robertson et al. [31] have also reported the formation of very high quality thin In(y)Al(x)Sb(1-x-y) films grown by magnetron epitaxy with thicknesses much greater than the equilibrium critical thickness. They showed that single layers of InAlSb could be grown coherently on (001) InSb for Al concentrations approaching 13-15% despite the relatively high plasma energies involved in the sputtering process. However, the authors observed small (< 20 Å) In-rich regions in all the bilayer, superlattice and buffers layers investigated [31]. Based on the crystallinity of the films containing 18% Al (figure 1 and table 1), we prepared films with four different stoichiometries, with Al concentration varying from 0-18% (considering the total number of atoms in the compound). The atomic concentration was estimated by PIXE and RBS analyses, as shown in the next subsection. The In(y)Al(x)Sb(1-x-y) films are very stable and no degradation signs or changes in composition have been identified in samples stored at room temperature, ambient pressure, with no particular care about exposure to light, within two year period.

8

3.2. Atomic composition and structural characterization of In(y)Al(x)Sb(1-x-y) films The elemental composition of the films was probed by RBS (figure 2) and PIXE analyses. The RBS spectra were simulated with the SIMNRA code [23] to estimate the relative concentration of In, Al, Sb, and O in the films. The main parameters obtained from the simulations are presented in table 2. The resolution of the RBS technique is not high enough to distinguish between In and Sb backscattered ions, whose atomic masses are very close to each other. Hence, the RBS and PIXE analyses were combined to estimate the relative atomic composition of the films. For the sake of clarity, peak amplitudes in the RBS spectra were normalized and spectra corresponding to films with different Al concentrations were offset vertically. The inset shows a magnified view of the Al edge for films with different Al concentrations. According to the PIXE analysis (table 3), the Sb:In ratio in the InSb film is approximately 1:1, as expected. By increasing the Al concentration in In(y)Al(x)Sb(1-x-y) films, we induced an increase in the Sb:In ratio from 1.3 to 1.9. Films with the highest Al concentrations also presented a thickness increment, measured directly by scanning electron microscopy, whose results are shown in table 2. This is due to the higher deposition rate of Sb, compared to the InSb and Al ones, and the need to equalize the amount of Sb and Al on the films. We opted for maintaining the InSb power at a fixed value to minimize the number of variables, thus resulting in films with different thicknesses. Finally, it is worth mentioning that, as can be seen in table 2, the oxygen concentration in the films proportionally increases with that of Al. This behavior can be explained by the high reactivity of Al with oxygen. The levels of O contamination are in conformity, within the respective measurement uncertainties, to those of 300 nm InSb and GaSb films deposited by magnetron sputtering at 400°C [21].

9

In(y)Al(x)Sb(1-x-y) films can also be deposited by magnetron sputtering via a mixture of AlSb and InSb, and for those the structure of In(y)Al(x)Sb(1-x-y) films is also strongly influenced by deposition temperature. According to Jachimowski [22], In(y)Al(x)Sb(1-x-y) films deposited by DC sputtering are either amorphous or polycrystalline depending on the temperature of the substrate onto which the material is deposited. Films prepared by deposition onto unheated substrates showed amorphous structure, whilst polycrystalline films were obtained by deposition onto substrates heated to 300°C, in agreement with the results shown here. In(y)Al(x)Sb(1-x-y) layers grown on semi-insulating GaAs (100) by MBE were also reported: heterostructures composed of In(y)Al(x)Sb(1-x-y) and AlSb layers were grown with thicknesses dInAlSb and dAlSb

[32].

Figure 3 shows diffraction patterns (GIXRD) of In(y)Al(x)Sb(1-x-y) films deposited on SiO2/Si by magnetron sputtering with different Al concentrations. These diffraction patterns are characteristic of a polycrystalline compound with zincblende phase. The main peaks for all samples (except for 9% and 15% Al, which are shown on the inset) and the respective crystallographic orientations are indicated on the graph. The intensity ratio of the peaks for those samples is similar to that of powder standards, indicating the films are composed of randomly oriented crystallites. All samples deposited at 420 °C exhibit the Sb2O3 contribution (shoulder to the left of the (1 1 1) peak). The increase in Al concentration yields an evident shift in the position of the diffraction peaks, resulting from changes in the lattice constant. The inset of figure 3 shows a magnified view of the diffraction peaks located at 2θ between 46 and 50 degrees, where this shift can be easily seen. The calculated equilibrium lattice constant a of In(y)Al(x)Sb(1-x-y) as a function of the Al concentration (x) is shown in Figure 4 (GIXRD measurements were performed at

10

300 K). Moreover, the lattice constants calculated in this paper, using Bragg’s law are in agreement with Vegard’s law, which is an empirical rule that states that a property value of an compound (the lattice constant in our case) can be determined from a linear interpolation of the property values of its constituent elements or, in the case of higher order compounds, constituent compounds [33]. Fitting the calculated results gives the following linear equation, compatible with Vegard’s law (equation 1):

(

(

)

[

)

( )

(

)]

(1)

The decrease in a with increasing x implies that the interatomic distance is decreasing. Thus, the binding forces of the valence electrons with their atoms will increase, so an additional force will be required to move these electrons from the valence band to the conduction band, inducing an increase in bandgap energy, a characteristic presented by In(y)Al(x)Sb(1-x-y) [16] and other compounds of zincblende structure [34]. In practice, the relationship between bandgap and lattice constant is nonlinear, where, for cubic crystalline semiconductors, the bandgap is inversely proportional to the square of the lattice constant [35], although the linear approximation is valid for small regions. The commonly accepted data on the bandgap of In(y)Al(x)Sb(1-x-y) alloys [36], at 300 K, were obtained by Agaev and Bekmedova, who studied a series of five polycrystalline alloy samples in which the Al content varied from 5 to 30% (converted to the notation of this work ) (above 30% the bandgap becomes indirect). Subsequent electroreflectance measurements at room temperature by Isomura et al. determined the bowing parameter c = 0.43 [37], allowing us to write ( where ` =

)

,

(2)

, converting to our ternary compound notation.

11

3.3. Surface chemical composition Figure 5 shows XPS results for In(y)Al(x)Sb(1-x-y) samples deposited at 420 °C, measured with 1840 eV photon energy. Spectra from samples with different Al concentrations were vertically offset for clarity. Since the Sb 3d5/2 peak overlaps with the O 1s one, the Sb 3d3/2 peak was analyzed in order to obtain the chemical components associated. The Sb 3d3/2 XP spectra are shown at the center of figure 5, with three main components related to the Sb–In (~537.0 eV) [38], Sb-Sb (~537.20 eV) and Sb–O (539.7 eV) bonds. The contribution from Sb-O appears dislocated by ~2.8 eV from the Sb-In one [39]. The ratio between the intensities associated to the Sb–Sb and Sb–O components, ISb-Sb / ISb-O, increases from 0 to 0.36 when the Al relative concentration increases from 0 to 18%. The In 3d5/2 spectra are shown on the left panel of figure 5. The contribution from In–O appears separated by 0.9 eV from the In–Sb one [38]. The ratio between the intensities associated to the In–Sb and In–O components, IIn-Sb / IIn-O, decreases from 1.67 to 1.05 when the Al relative concentration increases from 0 to 18%, showing significant impoverishment of any In component at the surface. The Al 1s spectra are shown on the right panel of figure 5, with one main component related to the Al–O bond (1561 eV). The presence of Al–O bond was also confirmed with the analysis of Al 2p spectra (74.4 eV) (not shown) [40], suggesting there is no Al-Sb bond (537.7) [41] from the surface to a depth of 33.3 Å in In(y)Al(x)Sb(1-x-y) films, since the corresponding mean free path of photoelectrons from the Al 1s peak and the Al 2p peak are respectively

7.8 Å and 33.3 Å [41,42]. These

results agree well with the Sb 3d3/2 XP spectra, which shows no Sb-Al bonding for the depth investigated here. According to the GIXRD results shown in figure 3, no appreciable amount of Sb in its crystalline, metallic phase, is present in the film.

12

GIXRD and XPS are complementary techniques, probing different depths in the same sample. While XPS provides information about the first few nanometers from the surface, GIXRD takes an average over the entire thickness of the films, hence the different outcomes. By combining both results we can infer that oxidation starts at the surface and diminishes towards the interior of the films. The positions of the XPS peaks corresponding to the Sb 3d 3/2 of the In(y)Al(x)Sb(1-x-y) films presented here are in agreement with the positions found by Clark et al. [43]. In relation to the In 3d5/2, Al 2p and Al 1s peaks of the In(y)Al(x)Sb(1-x-y), there seems to be no information available in the literature yet. On the other hand, according to Ramelan et al., a distinct behavior is observed on the surface of epitaxial Al(y)Ga(x)Sb(1-x-y) layers on GaAs grown by Metal Organic Chemical Vapor Deposition (MOCVD) [44]. In this paper, it was found that the percentage of the Al-O bond is especially high compared with a small percentage of Al-Sb bond (not present in In(y)Al(x)Sb(1-x-y) films ), which was accentuated by a treatment with argon ion milling for 90 s. 5. Conclusions We report on the formation of polycrystalline In(y)Al(x)Sb(1-x-y) films by magnetron sputtering deposition on SiO2/Si substrates, with variable Al and In relative concentrations. GIXRD analysis reveals that the In(y)Al(x)Sb(1-x-y) films are polycrystalline with zincblende phase, the lattice parameter of the ternary compound being easily tuned according to the Al relative concentration: the higher Al concentration, the smallest lattice parameter (and consequently bandgap energy associated with it). RBS analysis indicates that the total amount of O in the films increases proportionally to the amount of Al. XPS analysis shows that the surface of

13

the films is composed of a mixture of In-Sb, In-O, Sb-Sb, Sb-O, Sb-In and Al-O, with no indication of the presence of Al-Sb. Declarations of interest: None

Acknowledgements This work was financially supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico and Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul. The authors thank Ion Implantation Laboratory at UFRGS, Laboratório de Conformação nanométrica at UFRGS and LNLS for their continued technical assistance.

References

[1]

H.K. Choi, S.J. Eglash, Room-temperature cw operation at 2.2 m of GalnAsSb/AIGaAsSb diode lasers grown by molecular beam epitaxy, Appl. Phys. Lett. 59 (1991) 1165–1166. doi:10.1063/1.105544.

[2]

H. Zhao, Y. Chen, J.H. Yum, Y. Wang, F. Zhou, F. Xue, J.C. Lee, Effects of barrier layers on device performance of high mobility In0.7Ga0.3As metal-oxidesemiconductor field-effect-transistors, Appl. Phys. Lett. 96 (2010) 102101. doi:10.1063/1.3350893.

[3]

R.J.W. Hill, D.A.J. Moran, X. Li, H. Zhou, D. Macintyre, S. Thoms, A. Asenov, P. Zurcher, K. Rajagopalan, J. Abrokwah, R. Droopad, M. Passlack, I.G. Thayne, Enhancement-Mode GaAs MOSFETs With an In0.3Ga0.7As and Channel, a Mobility of Over 5000 cm2 and Transconductance of Over 475 µS / µm, IEEE Electron Device Lett. 28 (2007) 1080–1082. doi:10.1109/LED.2007.910009.

[4]

D.H. Chow, R.H. Miles, C.W. Nieh, T.C. Mcgill, Growth of InAs / Ga1-xInxSb infrared superlattices, J. Cryst. Growth. 111 (1991) 683–687. doi:10.1016/00220248(91)91063-G.

[5]

L. Shkedy, T. Markovitz, Z. Calahorra, I. Hirsh, I. Shtrichman, Megapixel digital InSb detector for midwave infrared imaging, Opt. Eng. 50 (2011) 061008. 14

doi:10.1117/1.3572163. [6]

T. Zhang, S.K. Clowes, M. Debnath, A. Bennett, C. Roberts, J. Harris, R. Stradling, L. Cohen, T. Lyford, P. Fewster, High-mobility thin InSb films grown by molecular beam epitaxy, Appl. Phys. Lett. 84 (2004) 4463–4465. doi:10.1063/1.1748850.

[7]

D. Chow, H. Dunlap, W. Williamson, S. Enquist, B. Gilbert, S. Subramaniam, P. Lei, G. Bernstein, InAs/AISb/GaSb Resonant Interband Tunneling Diodes and Au-on-InAs/A1Sb-Superlattice Schottky Diodes for Logic Circuits, IEEE Electron Device Lett. 17 (1996) 69–71. doi:10.1109/55.484126.

[8]

J. Meyer, L. Olafsen, E. Aifer, W. Bewley, C. Felix, I. Vurgaftman, M. Yang, L. Goldberg, D. Zhang, C. Lin, S. Pei, D. Chow, Type II W, interband cascade and vertical-cavity surface-emitting mid-IR lasers, IEE Proceedings-Optoelectronics. 145 (1998) 275–280. doi:10.1049/ip-opt:19982304.

[9]

Y. Mao, X.X. Liang, G.J. Zhao, T.L. Song, Lattice parameters and band structure of ternary mixed crystals Al x Ga 1 − x As from first-principle calculations, in: 2nd Int. Conf. Math. Model. Phys. Sci., 2014. doi:10.1088/17426596/490/1/012172.

[10] R. Rousina, H. C., J.B. Webb, Growth and characterization of In1−x Ga x Sb by metalorganic magnetron sputtering, J. Appl. Phys. 68 (1990) 2181–2186. doi:10.1063/1.346546. [11] I. Vurgaftman, J.R. Meyer, L. RamMohan, High-Power / Low-Threshold Type-II Interband Cascade Mid-IR Laser — Design and Modeling, IEEE Photonics Technol. Lett. 9 (1997) 170–172. [12] T. Ashley, T.M. Burke, M.T. Emeny, N.T. Gordon, D.J. Hall, D.J. Lees, C. Little, D. Milner, Epitaxial InSb for elevated temperature operation of large IR focal plane arrays, in: Infrared Technol. Appl. XXIX, 2003: pp. 95–102. doi:10.1117/12.503527. [13] M.K. Haigh, G.R. Nash, S.S. J., B. L., E.M. T., A. T., Mid-infrared Al x In 1 − x Sb light-emitting diodes, Appl. Phys. Lett. 90 (2007) 231116. doi:10.1063/1.2745256. [14] H. Fujita, K. Ueno, O. Morohara, E. Camargo, H. Geka, Y. Shibata, N. Kuze, AlInSb Mid-Infrared LEDs of High Luminous Efficiency for Gas Sensors, Phys. Status Solidi A. 215 (2018) 1700449. doi:10.1002/pssa.201700449. [15] B.I. Mirza, N.G. R., S.J. Smith, L. Buckle, S.D. Coomber, M.T. Emeny, T. 15

Ashley, Recombination processes in midinfrared Al x In 1 − x Sb light-emitting diodes, J. Appl. Phys. 104 (2008) 063113. doi:10.1063/1.2982374. [16] N. Dai, F. Brown, R.E. Doezema, S.J. Chung, K.J. Goldammer, M. Santos, Determination of the concentration and temperature dependence of the fundamental energy gap in AlxIn1−xSb of the fundamental energy gap in AlxIn1−xSb, Appl. Phys. Lett. 73 (1998) 3132–3134. doi:10.1063/1.122696. [17] V. Dahiya, J.I. Deitz, D.A. Hollingshead, J.A. Carlin, T.J. Grassman, S. Krishna, Investigation of digital alloyed AlInSb metamorphic buffers, J. Vac. Sci. Technol. B. 36 (2018) 02D111. doi:10.1116/1.5018260. [18] J. Li, X-Ray Characterization of CuPt Ordered III-V Ternay Alloys, in: A. Mascarenhas (Ed.), Spontaneous Ordering Semicond. Alloy., Springer Science+Business Media, Colorado, 2002: pp. 165–192. doi:10.1007/978-14615-0631-7. [19] S. Swann, Magnetron sputtering, Phys. Technol. 19 (1988) 67–75. doi:10.1088/0305-4624/19/2/304. [20] P.J. Kelly, R.D. Arnell, Magnetron sputtering : a review of recent developments and applications, Vacuum. 56 (2000) 159–172. doi:10.1016/S0042207X(99)00189-X. [21] R. Giulian, D.J. Manzo, J.B. Salazar, W. Just, A.M.H. de Andrade, J.R. Schoffen, L.A.B. Niekraszewicz, J.F. Dias, F. Bernardi, Structural and electronic characterization of antimonide films made by magnetron sputtering, J. Phys. D. Appl. Phys. 50 (2017) 075106. doi:10.1088/1361-6463/aa5368. [22] M. Jachimowski, A. Data, DC sputtered AlxIn1-xSb films, Thin Solid Films. 48 (1978) L15–L17. doi:10.1016/0040-6090(78)90003-2. [23] M. Mayer, SIMNRA, a simulation program for the analysis of NRA, RBS and ERDA, in: AIP Conf. Proc., 1999: pp. 541–544. http://aip.scitation.org/doi/abs/10.1063/1.59188. [24] W. Yongqiang, N. Michael, Handbook of Modern Ion Beam Materials Analysis, 2nd ed., 2009. [25] J.A. Maxwell, J.L. Campbell, W.J. Teesdalle, The guelph PIXE software package, Nucl. Instruments Methods Phys. B. 43 (1989) 218–230. doi:10.1016/0168-583X(89)90042-6. [26] H. Tolentino, V. Compagnon-Cailhol, F.C. Vicentin, M. Abbate, The LNLS soft X-ray spectroscopy beamline, J. Synchrotron Radiat. 5 (1998) 539–541. 16

doi:10.1107/S0909049597016087. [27] R. Giulian, D.J. Manzo, C.A. Bolzan, F. Bernardi, A.M.H. de Andrade, J.R. Schoffen, D.L. Baptista, Ion irradiation effects on Sb-rich GaSb films, Mater. Res. Express. 6 (2019) 026425. doi:10.1088/2053-1591/aaf0c8. [28] I. Ishu, P. Barman, Surface Modification of Sputtered Ga.5In.5Sb Thin Films, J. Appl. Sci. Environ. Manag. 11 (2007) 31–34. [29] R. Bernal-Correa, S. Gallardo-Hernandez, J. Cardona-Bedoya, A. Pulzara-Mora, Structural and optical characterization of GaAs and InGaAs thin films deposited by RF magnetron sputtering, Optik (Stuttg). 145 (2017) 608–616. doi:10.1016/j.ijleo.2017.08.042. [30] R.C. Sharma, M. Srivastava, PHASE CALCULATIONS OF AL-IN AND ALIN-SB SYSTEMS, Calphad- Comput. Coupling Phase Diagrams Thermochem. 16 (1992) 409–426. [31] M.D. Robertson, J.M. Corbett, J.B. Webb, Transmission Electron Microscopy Characterization of InA1Sb / InSb Bilayers and Superlattices, Micron. 28 (1997) 175–183. [32] O.S. Komkov, A.N. Semenov, D.D. Firsov, B.Y. Meltser, V.A. Solov’ev, T. V. Popova, A.N. Pikhtin, S. V. Ivanov, Optical Properties of Epitaxial Al x In1−x Sb Alloy Layers, Semiconductors. 45 (2011) 1425–1429. doi:10.1134/S1063782611110145. [33] N.W. Ashcroft, A.R. Denton, Vegard’s Law, Phys. Rev. A. 43 (1991) 3161– 3164. doi:10.1103/PhysRevA.43.3161. [34] I. Vurgaftman, J.R. Meyer, Band parameters for III – V compound semiconductors and their alloys, J. Appl. Phys. 5815 (2001) 5815–5875. doi:10.1063/1.1368156. [35] R. Dalven, Empirical relation between energy gap and lattice constant in cubic semiconductors, Phys. Rev. B. 8 (1973) 6033–6034. doi:10.1103/PhysRevB.8.6033. [36] S. Adachi, Properties of Semiconductor Alloys: Group-IV, III–V and II–VI Semiconductors, 2009. [37] S. Isomura, D. Prat, J.C. Woolley, Electroreflectance Spectra of AlxIn1-xSb alloys, Phys. Stats. Sol. 65 (1974) 213–219. doi:10.1002/pssb.2220650119. [38] W.K. Liu, W.. Yuen, R.A. Stradling, Preparation of InSb substrates for molecular beam epitaxy, J. Vac. Sci. Technol. B. 13 (1995) 1539–1545. 17

doi:10.1116/1.588184. [39] T. V. Lvova, M.S. Dunaevskii, M. V. Lebedev, a. L. Shakhmin, I. V. Sedova, S. V. Ivanov, Chemical passivation of InSb (100) substrates in aqueous solutions of sodium sulfide, Semiconductors. 47 (2013) 721–727. doi:10.1134/S106378261305014X. [40] A.H. Ramelan, K.S.A. Butcher, E.M. Goldys, T.L. Tansley, High-resolution Xray photoelectron spectroscopy of AlxGa1-xSb, Appl. Surf. Sci. 229 (2004) 263– 267. doi:10.1016/j.apsusc.2004.02.001. [41] M. Stjerndahl, H. Bryngelsson, T. Gustafsson, J.T. Vaughey, M.M. Thackeray, K. Edström, Surface chemistry of intermetallic AlSb-anodes for Li-ion batteries, Electrochim. Acta. 52 (2007) 4947–4955. doi:10.1016/j.electacta.2007.01.064. [42] S. Tanuma, C.J. Powell, D.R. Penn, Calculations of electron inelastic mean free paths . VIII . Data for 15 elemental solids over the 50 – 2000 eV range, Surf. Interface Anal. 37 (2005) 1–14. doi:10.1002/sia.1997. [43] S.A. Clark, J.W. Cairns, S.P. Wilks, R.H. Williams, A.D. Johnson, C.R. Whitehouse, Antimony capping and decapping of InAlSb(100), Surf. Sci. 336 (1995) 193–198. doi:10.1016/0039-6028(95)00503-X. [44] A.H. Ramelan, H. Harjana, P. Arifin, Growth of AlGaSb compound semiconductors on GaAs substrate by metalorganic chemical vapour deposition, Adv. Mater. Sci. Eng. (2010) 923409. doi:10.1155/2010/923409.

18

LIST OF FIGURE AND TABLE CAPTIONS

Fig1.eps - Diffraction patterns obtained by grazing incidence x-ray diffraction of In(y)Al(x)Sb(1-x-y) films for different deposition parameters, as listed in table 1.

19

Fig2.eps - The Rutherford backscattering spectrometry analysis of selected samples. The Spectra are vertically offset for clarity.

20

Fig3.eps - Grazing incidence x-ray diffraction measurements of In(y)Al(x)Sb(1-x-y) films deposited on SiO2/Si by magnetron sputtering with different Al concentrations. The main graph shows the diffraction pattern of representative samples, while the inset shows a magnified view of the peaks located between 46-50 degrees, for all samples investigated, where the shift in diffraction angle due to the increase in Al concentration can be readily seen.

21

Fig4.eps - Lattice constant as a function of Al concentration in In(y)Al(x)Sb(1-x-y) compounds, with 0 % and 50% representing respectively InSb and AlSb. The line represents Vegard’s law estimated from equation 1. Values extracted from references [16] and [34] are also shown for comparison

22

Fig5. eps - X-ray photoelectron spectra of In(y)Al(x)Sb(1-x-y) films with different Al concentrations, measured at 1840 eV photon energy. (a) In 3d5/2, (b) Sb 3d3/2 and (c) Al 1s. TABLE 1

RF Power

DC Power

RF Power

(W) applied

(W) applied

(W) applied

to the InSb

to the Al

to the Sb

target

target

target

28

100

65

19

3.4

24

100

53

16

3.3

21

100

40

13

3.1

20

100

27

10

2.7

18

100

65

30

2.2

Al concentration (at.%)

PAl/ PSb

23

Table 1 – Sputtering deposition parameters for each individual target and relative Al concentration in the films. PAl/ PSb is the ratio between the power applied to the Al and Sb targets.

TABLE 2 Thickness

Areal

(nm)

density (1015

In (at.%)

Al ( at.%)

Sb (at.%)

O (at.%)

-2

at cm ) InSb

In(y)Al(x)Sb(1-x-y)

341

955

48

0

48

4

358 425 449

1245 1477 1620

37 28 23

9 15 20

47 45 44

7 12 13

Table 2 - Relative elemental concentration from Rutherford backscattering spectrometry analysis of In(y)Al(x)Sb(1-x-y) films deposited on SiO 2/Si by magnetron sputtering at 420°C. The thickness of the films was measured directly from scanning electron microscopy images. All values have an uncertainty of approximately 10%.

TABLE 3

InSb

In(y)Al(x)Sb(1-x-y)

In (at.%)

Al ( at.%)

Sb (at.%)

Sb:In ratio

50

0

50

1.0

40 33 28

9 14 19

51 53 53

1.3 1.6 1.9

Table 3 - Relative elemental concentration from particle induced x-ray emission analysis of In(y)Al(x)Sb(1-x-y) films. All values have an uncertainty of approximately 10%.

24