scholarly journals Plasma-Assisted MOCVD Growth of Non-Polar GaN and AlGaN on Si(111) Substrates Utilizing GaN-AlN Buffer Layer

Coatings ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 94
Author(s):  
Pepen Arifin ◽  
Heri Sutanto ◽  
Sugianto ◽  
Agus Subagio

We report the growth of non-polar GaN and AlGaN films on Si(111) substrates by plasma-assisted metal-organic chemical vapor deposition (PA-MOCVD). Low-temperature growth of GaN or AlN was used as a buffer layer to overcome the lattice mismatch and thermal expansion coefficient between GaN and Si(111) and GaN’s poor wetting on Si(111). As grown, the buffer layer is amorphous, and it crystalizes during annealing to the growth temperature and then serves as a template for the growth of GaN or AlGaN. We used scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction (XRD) characterization to investigate the influence of the buffer layer on crystal structure, orientation, and the morphology of GaN. We found that the GaN buffer layer is superior to the AlN buffer layer. The thickness of the GaN buffer layer played a critical role in the crystal quality and plane orientation and in reducing the cracks during the growth of GaN/Si(111) layers. The optimum GaN buffer layer thickness is around 50 nm, and by using the optimized GaN buffer layer, we investigated the growth of AlGaN with varying Al compositions. The morphology of the AlGaN films is flat and homogenous, with less than 1 nm surface roughness, and has preferred orientation in a-axis.

2012 ◽  
Vol 442 ◽  
pp. 16-20
Author(s):  
Yong Wang ◽  
Nai Sen Yu ◽  
Ming Li ◽  
Kei May Lau

The continuous 1.0 µm GaN epilayers with and without partially Mg-doped were grown on Si (111) substrates by metal organic chemical vapor deposition (MOCVD). The DC current-voltage (I-V), time-of-flying secondary ion mass spectrometer (ToF-SIMS) and atomic force microscope (AFM) measurements were employed for comparison to characterize surface morphology and resistivity of GaN buffer layer with and without partially Mg-doped. The sample of 1.0 µm GaN epilayer with partially Mg-doped shows much higher resistivity than sample without Mg-doped, which indicates the partially Mg doping in 1.0 µm GaN epilayer can effectively increase the resistivity of GaN grown on Si (111) substrates. As a result, the high resistivity GaN buffer layer with good surface morphology is achieved in the partially Mg-doped GaN buffer layer.


Author(s):  
D. Aryanto ◽  
Z. Othaman ◽  
A. K. Ismail ◽  
A. S. Ameruddin

The single layer In0.5Ga0.5As quantum dots (QDs) were grown on a thin InxGa1-xAs underlying layer by metal-organic chemical vapor deposition(MOCVD) via Stranski-Krastanow growth mode. The effect of different indium composition in the InxGa1-xAs underlying layer was investigated usingatomic force microscopy (AFM). AFM images show that the QDs structures were formed on the surface. The dots formation on the surface changes withdifferent composition of InxGa1-xAs underlying layer. Increasing indium composition in the underlying layer resulted to formation of higher density andsmaller size dots. Several large dots were also formed on the surface. Growing of underlying layer reduces the lattice mismatch between In0.5Ga0.5As andGaAs, and decreases the critical thickness of the dots. This strongly influences the dots nucleation on the surface. Growth of quantum dots usingunderlying layer is one way to modify dot formation in order to achieve uniform QDs of right size and high density, which are essential for QDs deviceapplications.


2005 ◽  
Vol 892 ◽  
Author(s):  
Akihiro Hinoki ◽  
Yuichi Hiroyama ◽  
Tadayoshi Tsuchiya ◽  
Tomoyuki Yamada ◽  
Masayuki Iwami ◽  
...  

AbstractFor further improvements in AlGaN/GaN heterojunction field-effect transistor performance (HFET), it is necessary to reduce the leakage current of the GaN buffer layer. We found a correlation between the leakage current and the intensity of the yellow luminescence of GaN layers taken by UV lamp excitation. The GaN layers were grown by metal organic chemical vapor deposition on SiC substrates. When the samples were excited by a UV (365 nm) lamp, visible yellow luminescence was observed. The leakage current of the GaN buffer layer was measured after deposition of ohmic metal contact. We confirmed clear correlation between the leakage current and the luminescence intensity based from result that the samples with the larger leakage current showed the stronger luminescence intensity. This correlation gives us useful information to understand the drain-source leakage current of AlGaN/GaN HFET.


1990 ◽  
Vol 204 ◽  
Author(s):  
Erik O. Einset ◽  
Klavs F. Jensen ◽  
Thomas F. Kuech

ABSTRACTWe present an analysis of compositional variations in the growth of the compound semiconductor, InxGal-xAs, by metal organic chemical vapor deposition (MOCVD). A three dimensional transport model for fluid flow, heat, and mass transfer is solved using the finite element method. The Delta Lattice Parameter (DLP) model is used to describe the thermodynamics of the solid solution, and the Hertz-Langmuir equation is used to calculate the evaporation rate of indium from the growing crystal. Wall depletion is incorporated by allowing for explicit wall deposition of In vapor throughout the reactor.Comparison of model predictions with experimental observations by MOCVD of InGaAs in a horizontal reactor suggests that transport phenomena lead to composition variations across the substrate, and that solution thermodynamics have little effect on the InAs incorporation rate at a given deposition temperature. However, thermodynamic factors appear to influence the change in indium incorporation with growth temperature.


2006 ◽  
Vol 515 (4) ◽  
pp. 1527-1531 ◽  
Author(s):  
Jinzhong Wang ◽  
Vincent Sallet ◽  
Gaëlle Amiri ◽  
Jean-François Rommelluere ◽  
Alain Lusson ◽  
...  

Author(s):  
Г.С. Гагис ◽  
Р.В. Левин ◽  
А.Е. Маричев ◽  
Б.В. Пушный ◽  
М.П. Щеглов ◽  
...  

GaInPAs/InP heterostructures grown by low pressure (0.1 bar, 600 oC) metal-organic chemical vapor phase deposition were investigated. The thicknesses of grown GaInAsP layers were about 1 µm. For the epitaxial layers Ga<sub>1-x</sub>In<sub>x</sub>P<sub>1-y</sub>As<sub>y)</sub> with average compositions of x = 0.77 – 0.87 and y = 0.07 – 0.42 the variation of V group elements content y with the epilayer depth were revealed, weher the compositions of V-group elements were changed up to Δy = 0.1 atomic fractions in V group elements sublattice. In most cases, y change occurs in a GaInAsP region up to 200 nm thick adjacent to the InP. In some cases, y changes throughout the whole GaInPAs layer thickness. Fo the epitaxial layers with a satisfactory crystal perfection the less was the mismatch between the substrate and the GaInPAs epitaxial layer, the smaller was the value of Δy. For GaInPAs layers characterized by a low degree of crystal perfection and a high lattice mismatch between GaInAsP and InP layers, the value of Δy was about zero. These data let us suggest that the incorporation of atoms of the V group in the epitaxial layer strongly depends on elastic deformation of the growing monolayer, that is mismatched with the underlying crystal surface.


2012 ◽  
Vol 2 (1) ◽  
pp. 1
Author(s):  
Didik Aryanto ◽  
Zulkafli Othaman ◽  
Abd. Khamim Ismail

Self-assembled In0.5Ga0.5As quantum dots (QDs) were grown using metal-organic chemical vapor deposition (MOCVD) on GaAs (100) substrate with different number of stacking QDs layers. Surface study using atomic force microscopy (AFM) shows that surface morphology of the self-assembled QDs change with different number of stacking QDs layers caused by the previous QDs layers and the thickness of the GaAs spacer layers. PL measurement shows variation in the PL spectra as a function of number of stacking layers of In0.5Ga0.5As QDs. The PL peak positions blue-shifted from 1225 nm to 1095 nm and dramatically increase in intensity with increasing number of stacking QDs layers.


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