scholarly journals Low-Temperature Epitaxial Growth of AlN Thin Films on a Mo Electrode/Sapphire Substrate Using Reactive Sputtering

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 443
Author(s):  
Jihong Kim

High-crystalline aluminum nitride (AlN) thin films are essential for device applications, and epitaxial growth is a promising approach to improve their crystalline quality. However, a high substrate temperature is usually required for the epitaxial growth, which is not compatible with the complementary metal-oxide-semiconductor (CMOS) process. Furthermore, it is very difficult to obtain epitaxial AlN thin films on the deposited metal layers that are sometimes necessary for the bottom electrodes. In this work, epitaxial AlN thin films were successfully prepared on a molybdenum (Mo) electrode/sapphire substrate using reactive sputtering at a low substrate temperature. The structural properties, including the out-of-plane and in-plane relationships between the AlN thin film and the substrate, were investigated using X-ray diffraction (XRD) 2θ-ω, rocking curve, and pole figure scans. Additional analyses using scanning electron microscopy (SEM), atomic force microscopy (AFM), and transmission electron microscopy (TEM) were also carried out. It was shown that highly c-axis-oriented AlN thin films were grown epitaxially on the Mo/sapphire substrate with an in-plane relationship of AlN [112¯0]//sapphire [101¯0]. This epitaxial growth was attributed to the highly ordered and oriented Mo electrode layer grown on the sapphire substrate. In contrast, the AlN deposition on the Mo/SiO2/Si substrate under the same conditions caused poorly oriented films with a polycrystalline structure. There coexisted two different low-crystalline phases of Mo (110) and Mo (211) in the Mo layer on the SiO2/Si substrate, which led to the high mosaicity and polycrystalline structure of the AlN thin films.

2006 ◽  
Vol 297 (1) ◽  
pp. 80-86 ◽  
Author(s):  
Hideto Yanagisawa ◽  
Satoko Shinkai ◽  
Katsutaka Sasaki ◽  
Junpei Sakurai ◽  
Yoshio Abe ◽  
...  

1994 ◽  
Vol 9 (11) ◽  
pp. 2959-2967 ◽  
Author(s):  
Kiyotaka Wasa ◽  
Toshifumi Satoh ◽  
Kenji Tabata ◽  
Hideaki Adachi ◽  
Yasumufi Yabuuchi ◽  
...  

The microstructures of sputtered thin films of lead-lanthanum zirconate-titanate (PLZT) on (0001) sapphire substrate have been studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Thin films of polycrystalline PLZT (9/65/35), Pb0.91La0.09Zr0.65Ti0.35O3, were prepared on a (0001) sapphire substrate by reactive sputtering, using the dc-magnetron system with a multitarget, Pb, La, Zr, and Ti at the substrate temperature of 700 °C. The PLZT thin films comprised (111) oriented small crystallites of PLZT. Although the average direction of the crystal orientation corresponded to the ideal epitaxial relationship (111) PLZT ‖ (0001) sapphire, the individual crystallites showed misalignment in both the growth direction and the film plane. The thin films could not be considered epitaxially grown films. From analysis of the TEM images, there exists an interfacial region between the PLZT thin film and the substrate. The interfacial region comprises ordered clusters of (111), disordered (101), and/or (110) PLZT crystallites. The presence of the interfacial region will suppress ideal epitaxial growth with uniform crystal orientation. It is confirmed that the addition of the buffer layer of graded composition of PLT-PLZT, between the substrate and the PLZT thin film, will suppress the formation of the disordered interfacial region and will enhance the epitaxial growth of the (111) PLZT on (0001) sapphire with three-dimensional crystal orientations.


Author(s):  
F.-R. Chen ◽  
T. L. Lee ◽  
L. J. Chen

YSi2-x thin films were grown by depositing the yttrium metal thin films on (111)Si substrate followed by a rapid thermal annealing (RTA) at 450 to 1100°C. The x value of the YSi2-x films ranges from 0 to 0.3. The (0001) plane of the YSi2-x films have an ideal zero lattice mismatch relative to (111)Si surface lattice. The YSi2 has the hexagonal AlB2 crystal structure. The orientation relationship with Si was determined from the diffraction pattern shown in figure 1(a) to be and . The diffraction pattern in figure 1(a) was taken from a specimen annealed at 500°C for 15 second. As the annealing temperature was increased to 600°C, superlattice diffraction spots appear at position as seen in figure 1(b) which may be due to vacancy ordering in the YSi2-x films. The ordered vacancies in YSi2-x form a mesh in Si plane suggested by a LEED experiment.


2018 ◽  
Vol 17 (03) ◽  
pp. 1760039
Author(s):  
K. M. Dhanisha ◽  
M. Manoj Christopher ◽  
M. Abinaya ◽  
P. Deepak Raj ◽  
M. Sridharan

The present work deals with NiO/Si3N4 layers formed by depositing nickel oxide (NiO) thin films over silicon nitrate (Si3N[Formula: see text] thin films. NiO films were coated on Si3N4-coated Si substrate using magnetron sputtering method by changing duration of coating time and were analyzed using X-ray diffractometer, field emission-scanning electron microscopy, UV–Vis spectrophotometer and four-point probe method to study the influence of thickness on physical properties. Crystallinity of the deposited films increases with increase in thickness. All films exhibited spherical-like structure, and with increase in deposition time, grains are coalesced to form smooth surface morphology. The optical bandgap of NiO films was found to decrease from 3.31[Formula: see text]eV to 3.22[Formula: see text]eV with upsurge in the thickness. The film deposited for 30[Formula: see text]min exhibits temperature coefficient resistance of [Formula: see text]1.77%/[Formula: see text]C as measured at 80[Formula: see text]C.


2019 ◽  
Vol 59 ◽  
pp. 126-136
Author(s):  
Radia Kalai ◽  
Amara Otmani ◽  
Lakhdar Bechiri ◽  
Noureddine Benslim ◽  
Abdelaziz Amara ◽  
...  

Structural, optical and electrical properties of SnO2 thin films deposited by spray ultrasonic technique were investigated by varying substrate temperature. The structural characterization of the films was analyzed via X-ray diffraction (XRD) technique and transmission electron microscopy (TEM). Films surface morphologies were studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Optical absorption spectrum was recorded using the UV–Vis spectroscopy and the films were found to be transparent. Optical measurements showed that the layers had a relatively high absorption coefficient of 105 cm−1. A shift in the absorption edge was observed and the films exhibited direct transitions with band gap energies ranging from 3.85 to 3.94 eV.


CrystEngComm ◽  
2019 ◽  
Vol 21 (23) ◽  
pp. 3552-3556 ◽  
Author(s):  
Ryosuke Kikuchi ◽  
Toru Nakamura ◽  
Yasushi Kaneko ◽  
Kazuhito Hato

Two-step growth makes it possible to grow NbON epitaxial films and minimize anion-related defects in the NbON films.


1994 ◽  
Vol 235-240 ◽  
pp. 665-666 ◽  
Author(s):  
C. Thivet ◽  
M. Guilloux-Viry ◽  
J. Padiou ◽  
A. Perrin ◽  
G. Dousselin ◽  
...  

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