Optimization of Annealing Conditions for ZnO-based Thin Films Grown Using MOCVD

2014 ◽  
Vol 1675 ◽  
pp. 3-8 ◽  
Author(s):  
Anas Mazady ◽  
Abdiel Rivera ◽  
Mehdi Anwar
Keyword(s):  
Thin Films ◽  
Lattice Mismatch ◽  
Chemical Vapor ◽  
Optical Quality ◽  
Crystal Quality ◽  
Zno Thin Films ◽  
Si Substrates ◽  
Annealing Conditions

ABSTRACTIn this work, effects of thermal annealing on the structural and optical properties of ZnO thin films grown on p-Si and GaN substrates using metalorganic chemical vapor deposition (MOCVD) are investigated. Annealing at 600 °C results in optimum crystal and optical qualities of the ZnO thin films on both substrates. Smaller lattice mismatch between grown ZnO epitaxial layer on GaN substrates results in better film morphology as compared to p-Si substrates. Higher annealing temperature along with a slower thermal ramp provides better crystal quality of ZnO thin films on both substrates. Annealing ZnO thin films at 700 °C with a slower thermal ramp results in better crystal quality as is evident from a 56% reduction in the full-width at half maximum (FWHM) of the (002) peak compared to the as-grown films. The optical quality also enhances with a slower annealing rate. The determination of the optimum annealing conditions for different substrates has important implications in fabricating optimized and efficient ZnO based electronics.

Growth and Characterization of Homoepitaxial ZnO Thin Films Grown by CVD

2006 ◽  
Vol 957 ◽  
Author(s):  
Christian Neumann ◽  
Joachim Sann ◽  
Stefan Lautenschläger ◽  
Frank Bertram ◽  
Jürgen Christen ◽  
...  
Keyword(s):  
Thin Films ◽  
Lattice Mismatch ◽  
Chemical Vapor ◽  
Wide Band ◽  
Optical Quality ◽  
Zno Thin Films ◽  
Homoepitaxial Growth ◽  
Extrinsic Defect ◽  
Bulk Single Crystals ◽  
P Type

ABSTRACTZnO as a direct wide-band-semiconductor with its band gap of 3.3 eV at room temperature is a promising optoelectronic material. The main obstacle in the ZnO system is its lack of achieving reproducible p-type conductivity. The main reasons for this are the high residual intrinsic and extrinsic defect concentrations which are still not completely understood.Homoepitaxial growth of ZnO and thus minimization of intrinsic defects due to lattice mismatch and incorporation of residual substrate species could be a solution to overcome these problems. Despite the availability of ZnO bulk single crystals reports regarding ZnO homoepitaxy are still quite rare. In this paper we report on a successful homoepitaxial growth of ZnO thin films by chemical vapor deposition (CVD).Atomic force microscopy shows that two-dimensional epitaxial growth was achieved without any additional buffer layer. With a rocking curve full width at half maximum (FWHM) of 17 arcsec the deposited films show a superior crystalline quality compared to its substrate. The optical quality of the epitaxial films has been characterized laterally by cathodoluminescence and spectrally by photoluminescence. Excitonic emissions at 4K are as narrow as 110 μeV. A dependence of the appearance of excitonic emissions from the growth polarity can be shown which is attributed to different incorporation rates of extrinsic defects.

Defects in β-SiC thin films grown on α-SiC substrates

1988 ◽  
Vol 46 ◽  
pp. 568-569
Author(s):  
Karren L. More
Keyword(s):  
Thin Films ◽  
Semiconductor Device ◽  
Lattice Mismatch ◽  
Chemical Vapor ◽  
Substrate Material ◽  
Growth Interface ◽  
Si Substrates ◽  
Thermal Expansion Coefficients ◽  
Device Applications ◽  
Expansion Coefficients

Beta-SiC is an ideal candidate material for use in semiconductor device applications. Currently, monocrystalline β-SiC thin films are epitaxially grown on {100} Si substrates by chemical vapor deposition (CVD). These films, however, contain a high density of defects such as stacking faults, microtwins, and antiphase boundaries (APBs) as a result of the 20% lattice mismatch across the growth interface and an 8% difference in thermal expansion coefficients between Si and SiC. An ideal substrate material for the growth of β-SiC is α-SiC. Unfortunately, high purity, bulk α-SiC single crystals are very difficult to grow. The major source of SiC suitable for use as a substrate material is the random growth of {0001} 6H α-SiC crystals in an Acheson furnace used to make SiC grit for abrasive applications. To prepare clean, atomically smooth surfaces, the substrates are oxidized at 1473 K in flowing 02 for 1.5 h which removes ∽50 nm of the as-grown surface. The natural {0001} surface can terminate as either a Si (0001) layer or as a C (0001) layer.

Plasma-Assisted MOCVD Growth of ZnO Thin Films

2005 ◽  
Vol 892 ◽  
Author(s):  
Maria Losurdo ◽  
Maria Michela Giangregorio ◽  
Pio Capezzuto ◽  
Giovanni Bruno ◽  
Graziella Malandrino ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Vapor Deposition ◽  
Metalorganic Chemical Vapor Deposition ◽  
Chemical Vapor ◽  
Optical Quality ◽  
Zno Thin Films ◽  
Zno Films ◽  
Mocvd Growth ◽  
Metalorganic Chemical

AbstractZnO thin films have been grown by metalorganic chemical vapor deposition (MOCVD) also plasma assisted (PA-MOCVD) on c-axis oriented sapphire (0001) and Si(001) substrates using the alternative Zn(TTA)2·tmed (HTTA=2-thenoyltrifluoroacetone,TMED=N,N,N’,N’-tetramethylethylendiamine) precursor. The structural, morphological and optical properties of ZnO films have been investigated. The results show that the O2 plasma assisted growth results in an improvement of the structure, in smoother morphologies and in a better optical quality with a sharp and intense exciton of ZnO films.

STRUCTURAL AND OPTICAL PROPERTIES OF ZnO SYNTHESIZED BY TEMPERATURE GRADIENT THERMAL OXIDATION

2010 ◽  
Vol 17 (05n06) ◽  
pp. 497-503 ◽  
Author(s):  
F. K. YAM ◽  
S. S. TNEH ◽  
Y.-Q. CHAI ◽  
W. S. LAU ◽  
Z. HASSAN ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Temperature Gradient ◽  
Thermal Oxidation ◽  
Optical Quality ◽  
Annealing Process ◽  
Zno Thin Films ◽  
Structural And Optical Properties ◽  
Fixed Temperature

In this work, a series of polycrystalline ZnO samples have been synthesized from Zn thin films deposited on Si (100) substrates by using thermal oxidation technique. The ZnO thin film samples grown by this technique were then characterized by a variety of structural and optical characterization tools. The results revealed that the use of novel annealing process i.e. the application of temperature gradient in the thermal treatment could enhance the structural and optical quality of the ZnO thin films significantly as compared to the normal annealing process, i.e. a fixed temperature under different durations. Apart from the improvement of structural and optical properties of ZnO thin films, another striking feature of this novel annealing process was the promotion of the growth of ZnO nanostructures.

Interactions Between Al and Cr Thin Films

1976 ◽  
Vol 34 ◽  
pp. 638-639
Author(s):  
R. M. Anderson ◽  
T. M. Reith ◽  
M. J. Sullivan ◽  
E. K. Brandis
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Vacuum System ◽  
Processing Temperature ◽  
Diffusion Couples ◽  
Electronic Circuits ◽  
Intermetallic Formation ◽  
Si Substrates ◽  
Aluminum Silicon

Thin films of aluminum or aluminum-silicon can be used in conjunction with thin films of chromium in integrated electronic circuits. For some applications, these films exhibit undesirable reactions; in particular, intermetallic formation below 500 C must be inhibited or prevented. The Al films, being the principal current carriers in interconnective metal applications, are usually much thicker than the Cr; so one might expect Al-rich intermetallics to form when the processing temperature goes out of control. Unfortunately, the JCPDS and the literature do not contain enough data on the Al-rich phases CrAl7 and Cr2Al11, and the determination of these data was a secondary aim of this work.To define a matrix of Cr-Al diffusion couples, Cr-Al films were deposited with two sets of variables: Al or Al-Si, and broken vacuum or single pumpdown. All films were deposited on 2-1/4-inch thermally oxidized Si substrates. A 500-Å layer of Cr was deposited at 120 Å/min on substrates at room temperature, in a vacuum system that had been pumped to 2 x 10-6 Torr. Then, with or without vacuum break, a 1000-Å layer of Al or Al-Si was deposited at 35 Å/s, with the substrates still at room temperature.

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.

Characteristics of ZnO thin films deposited onto Al/Si substrates by r.f. magnetron sputtering

1997 ◽  
Vol 302 (1-2) ◽  
pp. 116-121 ◽  
Author(s):  
Ki Hyun Yoon ◽  
Ji-Won Choi ◽  
Dong-Heon Lee
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Zno Thin Films ◽  
Si Substrates
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