Effects of morphology of buffer layers on ZnO/sapphire heteroepitaxial growth by RF magnetron sputtering

2015 ◽  
Vol 1741 ◽  
Author(s):  
Tomoaki Ide ◽  
Koichi Matsushima ◽  
Ryota Shimizu ◽  
Daisuke Yamashita ◽  
Hynwoong Seo ◽  
...  
Keyword(s):  
Rf Magnetron Sputtering ◽  
Buffer Layers ◽  
Crystal Nucleation ◽  
Zno Films ◽  
Growth Stages ◽  
Initial Growth ◽  
Height Distribution ◽  
Heteroepitaxial Growth ◽  
Distribution Profile

ABSTRACTEffects of surface morphology of buffer layers on ZnO/sapphire heteroepitaxial growth have been investigated by means of “nitrogen mediated crystallization (NMC) method”, where the crystal nucleation and growth are controlled by absorbed nitrogen atoms. We found a strong correlation between the height distribution profile of NMC-ZnO buffer layers and the crystal quality of ZnO films. On the buffer layer with a sharp peak in height distribution, a single-crystalline ZnO film with atomically-flat surface was grown. Our results indicate that homogeneous and high-density nucleation at the initial growth stages is critical in heteroepitaxy of ZnO on lattice mismatched substrates.

Effects of the Sputtering Time of AlN Buffer Layer on the Quality of ZnO Thin Films

2014 ◽  
Vol 881-883 ◽  
pp. 1117-1121 ◽  
Author(s):  
Xiang Min Zhao
Keyword(s):  
Thin Films ◽  
Buffer Layer ◽  
Rf Magnetron Sputtering ◽  
Buffer Layers ◽  
Zno Thin Films ◽  
Zno Films ◽  
Si Substrates ◽  
Atomic Force ◽  
Structure Morphology ◽  
Aln Buffer

ZnO thin films with different thickness (the sputtering time of AlN buffer layers was 0 min, 30 min,60 min, and 90 min, respectively) were prepared on Si substrates using radio frequency (RF) magnetron sputtering system.X-ray diffraction (XRD), atomic force microscope (AFM), Hall measurements setup (Hall) were used to analyze the structure, morphology and electrical properties of ZnO films.The results show that growth are still preferred (002) orientation of ZnO thin films with different sputtering time of AlN buffer layer,and for the better growth of ZnO films, the optimal sputtering time is 60 min.

Properties of Nano-ZnO Films Deposited by RF Magnetron Sputtering for SAW Biosensors

2011 ◽  
Vol 418-420 ◽  
pp. 293-296
Author(s):  
Qiu Yun Fu ◽  
Peng Cheng Yi ◽  
Dong Xiang Zhou ◽  
Wei Luo ◽  
Jian Feng Deng
Keyword(s):  
Magnetron Sputtering ◽  
Deposition Time ◽  
Rf Magnetron Sputtering ◽  
Zno Films ◽  
X Ray Diffraction ◽  
Zno Film ◽  
Nano Zno ◽  
Axis Orientation ◽  
X Ray

Abstract. In this article, nano-ZnO films were deposited on SiO2/Si (100) substrates by RF (radio frequency) magnetron sputtering using high purity (99.99%) ZnO target. The effects of deposition time and annealing temperature have been investigated. XRD (X-ray diffraction) and FSEM (Field Emission Scanning Electron Microscopy) were employed to characterize the quality of the films. The results show that the ZnO film with thickness of 600nm annealed at 900°C has higher quality of both C-axis orientation and crystallization. And for the Zone film with thickness of 300nm annealed at 850°C, the quality of both C-axis orientation and crystallization is higher than that annealed at 900°C and 950°C.

Growth of (0001) ZnO Thin Films on Sapphire

1996 ◽  
Vol 449 ◽  
Author(s):  
A. J. Drehman ◽  
P. W. Yip
Keyword(s):  
Surface Roughness ◽  
Buffer Layers ◽  
Zno Films ◽  
X Ray Diffraction ◽  
Axis Orientation ◽  
Force Microscopy ◽  
Sapphire Substrates ◽  
Atomic Force

ABSTRACTUsing reactive rf sputtering, we have grown (0001) oriented ZnO films in situ on heated c-axis sapphire substrates, that are promising, particularly in terms of surface roughness, as buffer layers for the subsequent epitaxial growth of III-V nitride films. We compare the effects of on-axis and off-axis sputter geometries on the film epitaxy and smoothness. We also examined the effect of substrate temperature on the growth and smoothness and quality of the film. X-ray diffraction was used to verify the hexagonal ZnO phase, its c-axis orientation and, qualitatively, the degree of its epitaxy. Atomic Force Microscopy (AFM) was used to determine the ZnO growth morphology and roughness. Our best films, obtained by off-axis sputter deposition, have a surface roughness of less than 1 nm.

Features of the Initial Growth Stages of ZnO Films on the Rhombohedral Plane of Sapphire

2019 ◽  
Vol 13 (6) ◽  
pp. 1234-1238 ◽  
Author(s):  
A. E. Muslimov ◽  
A. M. Ismailov ◽  
V. A. Babaev ◽  
V. M. Kanevsky
Keyword(s):  
Zno Films ◽  
Growth Stages ◽  
Initial Growth

Crystallinity and Photoluminescence Properties of ZnO Films on Zn Buffer Layers Deposited by rf Magnetron Sputtering

2007 ◽  
Vol 336-338 ◽  
pp. 567-570
Author(s):  
Chong Mu Lee ◽  
Anna Park ◽  
Young Joon Cho ◽  
Hyoun Woo Kim ◽  
Jae Gab Lee
Keyword(s):  
Thin Film ◽  
Magnetron Sputtering ◽  
Buffer Layer ◽  
Rf Magnetron Sputtering ◽  
Buffer Layers ◽  
Zno Films ◽  
Zno Thin Film ◽  
Zno Film ◽  
Amorphous Sio2 ◽  
Si Substrates

It is very desirable to grow ZnO epitaxial films on Si substrates since Si wafers with a high quality is available and their prices are quite low. Nevertheless, it is not easy to grow ZnO films epitaxially on Si substrates directly because of formation of an amorphous SiO2 layer at the interface of ZnO and Si. A Zn film and an undoped ZnO film were deposited sequentially on an (100) Si substrate by rf magnetron sputtering. The sample was annealed at 700°C in a nitrogen atmosphere. X-ray diffraction (XRD), photoluminescence (PL) and atomic force microscopy (AFM) analyses were performed to investigate the cristallinity and surface morphology of the ZnO film. According to the analysis results the crystallinity of a ZnO thin film deposited by rf magnetron sputtering is substantially improved by using a Zn buffer layer. The highest ZnO film quality is obtained with a 110nm thick Zn buffer layer. The surface roughness of the ZnO thin film increases as the Zn buffer layer thickness increases.

Microstructure of thin layers of MBE-grown GaAs on Si substrates

1986 ◽  
Vol 67 ◽  
Author(s):  
S. J. Rosner ◽  
S. M. Koch ◽  
J. S. Harris ◽  
S. Laderman
Keyword(s):  
Structural Evolution ◽  
Normal Growth ◽  
Optical Quality ◽  
Thin Layers ◽  
Buffer Layers ◽  
Initial Growth ◽  
Slow Growth Rate ◽  
Si Substrates ◽  
Ion Channeling

ABSTRACTThe ability to grow high quality epitaxial GaAs films directly on Si substrates has recently been demonstrated by Molecular Beam Epitaxy. Many of the most successful growth techniques include initial growth at low temperatures and slow growth rate to nucleate the compound on the elemental semiconductor with subsequent normal growth under conditions used for homoepitaxial GaAs MBE. The mechanisms for the success of this method are still poorly understood. This work focusses on a study of the structural evolution of this low temperature initial layer and conventionally grown overlayer. Thin films in the 5 to 300 nm range were used to evaluate the effect of the temperature and thickness on the growth process. Thicker films, described elsewhere, were used to evaluate the crystalline and optical quality of potential device layers.The structure of the thin buffer layers was studied as a function of both temperature and thickness. The crystalline quality of these layers was found to be quite poor, with substantial disorder at the GaAs/Si interface. The quality improved slowly as a function of thickness. The effect of the conventional overgrowth on this initil layer was also investigated. It was found that the quality of the low tumperature layer improved as normal overgrowth continued, as measured by ion channeling aligned yields. After 200 nm of overgrowth, ion channeling aligned yields from the material at the interface had declined substantially. This indicates that substantial regrowth and annealing of defects occurs as growth continues. These observations are further confirmed by TEM.

Heteroepitaxial growth of tungsten oxide films on silicon(100) using a BaF2 buffer layer

2003 ◽  
Vol 18 (12) ◽  
pp. 2859-2868 ◽  
Author(s):  
L.D. Doucette ◽  
F. Santiago ◽  
S.L. Moran ◽  
R.J. Lad
Keyword(s):  
Buffer Layer ◽  
Electron Cyclotron Resonance ◽  
Film Growth ◽  
Diffusion Processes ◽  
Electron Beam Evaporation ◽  
Growth Stages ◽  
Initial Growth ◽  
Heteroepitaxial Growth ◽  
Lattice Matching ◽  
Barium Tungstate

Multidomained heteroepitaxial WO3 films were grown on Si(100) substrates using a (111)-oriented BaF2 buffer layer at the WO3–Si interface. The 30-nm-thick BaF2 layer, grown by very low rate molecular-beam epitaxy, consisted of four equivalent crystalline domains oriented about the BaF2[111] axis, which provided templates for heteroepitaxial WO3 film growth. The WO3 films were grown by electron cyclotron resonance oxygen plasma-assisted electron beam evaporation of a WO3 source, and the temperature range was varied between 25°C and 600°C. At an optimal deposition temperature of approximately 450°C, monoclinic-phase WO3 films were produced, which consisted of coexisting (002), (020), and (200) in-plane orientations with respect to the BaF2(111)/Si(100) substrate. During growth, an interfacial barium tungstate (BaWO4) reaction product formed at the WO3–BaF2 interface. The {112} planes of this BaWO4 layer also have a multidomained heteroepitaxial orientation with respect to the BaF2(111) buffer layer. Postdeposition annealing experiments in air for 24 h at 400°C indicated that the heteroepitaxial BaWO4 and WO3 layers remain stable. A thermodynamic argument is used to explain the BaWO4 interfacial reaction during initial growth stages, and kinetically limited diffusion processes through the BaWO4layer coupled with lattice matching across the WO3–BaWO4 interface are proposed to be responsible for the formation of stable WO3 films at later growth stages.

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