Effect of annealing atmosphere (CO and N2 gas flow) on surface morphology and crystal quality of AlN buffer layer

ABSTRACTWe developed GaAs heteroepitaxy on a Si substrate by metalorganic vapor phase epitaxy (MOVPE) using tertiarybutylarsine (TBAs). In buffer layer growth at 450°C, the surface morphology and crystal quality of TBAs-grown films were slightly inferior to those of AsH3-grown films. At buffer layer growth below 400°C, the quality of TBAs-grown films improved. The GaAs films we grew using TBAs had a better quality than those grown using AsH2.

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Analysis of GaN-based HEMTS with AlN buffer layers by using Raman spectroscopy

Modern Physics Letters B ◽

10.1142/s0217984921410104 ◽

2021 ◽

pp. 2141010

Author(s):

Cheng Che Lee ◽

Hsin Jung Lee ◽

Hsin Che Lee ◽

Wei Yu Lee ◽

Wei Ching Chuang

Keyword(s):

Raman Spectroscopy ◽

Buffer Layer ◽

Epitaxial Layer ◽

Drain Current ◽

Buffer Layers ◽

Crystal Quality ◽

Subthreshold Slope ◽

Gan Hemts ◽

Aln Buffer

In this paper, AlGaN/GaN HEMTs with an AlN buffer layer were fabricated. Analyses on the crystal quality of the GaN epitaxial layer by Raman spectroscopy have been purposed. By introducing an AlN layer on sapphire substrate, the maximum drain current of the HEMT increased from 481 mA/mm to 522 mA/mm at [Formula: see text] V. Subthreshold slope was reduced from 638.3 mV/decade to 240.9 mV/decade and the electron mobility increased from 1109 cm2 V[Formula: see text]s[Formula: see text] to 1781 cm2 V[Formula: see text]s[Formula: see text]. These results showed that using an AlN buffer layer can improve the crystal quality of the GaN epitaxial layer, thus optimize the device performances of the GaN-based HEMTs.

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Preparation of InN by Means of AP-HCVD Using In Buffer Layers

MRS Proceedings ◽

10.1557/proc-1040-q09-32 ◽

2007 ◽

Vol 1040 ◽

Author(s):

Hiroaki Yokoo ◽

Naoki Wakiya ◽

Naonori Sakamoto ◽

Takato Nakamura ◽

Hisao Suzuki

Keyword(s):

Electrical Property ◽

Surface Morphology ◽

Buffer Layer ◽

Atmospheric Pressure ◽

Indium Nitride ◽

Buffer Layers ◽

Crystal Quality ◽

X Ray Diffraction ◽

X Ray ◽

Quality Surface

AbstractWe have grown indium nitride (InN) films using In buffer layer on an a-plane sapphire substrate under atmospheric pressure by halide CVD (AP-HCVD). Growth was carried out by two steps: deposition In buffer layer at 900 °C and subsequent growth of InN layer at 650 °C. In order to compare, we also grown InN films on an a-plane sapphire. The InN films are investigated on crystal quality, surface morphology and electrical property using high-resolution X-ray diffraction (HR-XRD), X-ray pole figure, scanning electron microscope (SEM), Hall measurement. The results show that the crystal quality, surface morphology and electrical property of InN films are improved by using In buffer layer.

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Effect of Buffer Layer and III/V Ratio on the Surface Morphology of Gan Grown by MBE

MRS Internet Journal of Nitride Semiconductor Research ◽

10.1557/s1092578300002829 ◽

1999 ◽

Vol 4 (S1) ◽

pp. 417-422 ◽

Cited By ~ 4

Author(s):

E. C. Piquette ◽

P. M. Bridger ◽

R. A. Beach ◽

T. C. McGill

Keyword(s):

Surface Morphology ◽

Buffer Layer ◽

Flux Ratio ◽

Plasma Source ◽

Growth Conditions ◽

Nitrogen Plasma ◽

Layer Growth ◽

Buffer Layers ◽

Flat Surfaces ◽

Aln Buffer

The surface morphology of GaN is observed by atomic force microscopy for growth on GaN and AlN buffer layers and as a function of III/V flux ratio. Films are grown on sapphire substrates by molecular beam epitaxy using a radio frequency nitrogen plasma source. Growth using GaN buffer layers leads to N-polar films, with surfaces strongly dependent on the flux conditions used. Flat surfaces can be obtained by growing as Ga-rich as possible, although Ga droplets tend to form. Ga-polar films can be grown on AlN buffer layers, with the surface morphology determined by the conditions of buffer layer deposition as well as the III/V ratio for growth of the GaN layer. Near-stoichiometric buffer layer growth conditions appear to support the flattest surfaces in this case. Three defect types are typically observed in GaN films on AlN buffers, including large and small pits and “loop” defects. It is possible to produce surfaces free from large pit defects by growing thicker films under more Ga-rich conditions. In such cases the surface roughness can be reduced to less than 1 nm RMS.

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Improvement in crystal quality of ZnO film on Si substrate by using a homo-buffer layer

Materials Science in Semiconductor Processing ◽

10.1016/j.mssp.2009.12.003 ◽

2009 ◽

Vol 12 (6) ◽

pp. 233-237 ◽

Cited By ~ 3

Author(s):

Jie Zhao ◽

Lizhong Hu

Keyword(s):

Buffer Layer ◽

Crystal Quality ◽

Zno Film ◽

Si Substrate

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Morphology and surface reconstructions of m-plane GaN

MRS Proceedings ◽

10.1557/proc-743-l4.1 ◽

2002 ◽

Vol 743 ◽

Cited By ~ 1

Author(s):

C. D. Lee ◽

R. M. Feenstra ◽

J. E. Northrup ◽

L. Lymperakis ◽

J. Neugebauer

Keyword(s):

Molecular Beam Epitaxy ◽

Low Temperature ◽

Surface Morphology ◽

Buffer Layer ◽

Molecular Beam ◽

Structural Quality ◽

Surface Reconstructions ◽

Gan Buffer Layer

ABSTRACTM-plane GaN(1100) is grown by plasma assisted molecular beam epitaxy on ZnO(1100) substrates. A low-temperature GaN buffer layer is found to be necessary to obtain good structural quality of the films. Well oriented (1100) GaN films are obtained, with a slate like surface morphology. On the GaN(1100) surfaces, reconstructions with symmetry of c(2×2) and approximate “4×5” are found under N- and Ga-rich conditions, respectively. We propose a model for Ga-rich conditions with the “4×5” structure consisting of ≥ 2 monolayers of Ga terminating the GaN surface.

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Improvement in Surface Morphology and Crystal Epitaxial CaF2 on Si (100) Through two Mbe Growth Stages

MRS Proceedings ◽

10.1557/proc-116-413 ◽

1988 ◽

Vol 116 ◽

Cited By ~ 3

Author(s):

Yoshihiro Morimoto ◽

Shoichiro Matsumoto ◽

Shoji Sudo ◽

Kiyoshi Yoneda

Keyword(s):

Surface Morphology ◽

Smooth Surface ◽

Growth Stage ◽

Early Growth ◽

Crystal Quality ◽

Growth Stages ◽

Optimum Conditions ◽

Si Substrate ◽

Mbe Growth

AbstractWe report the first study on improvement in surface morphology and crystal quality of as—grown epitaxial CaF2 film on a (100) Si substrate grown through two MBE growth stages without any post-growth treatment. The degree of improvement in surfacemorphology and crystal quality depends not only on the thickness of an initial thin CaF2 film grown at the early growth stage of 550ºC but also on both the subsrate temperature and thickness of a sequential grown CaF2 film used for thesecond growth stage. Under optimum conditions, the CaF2 films exhibited high quality with an RBS/channeling minimum yield of 4%, together with a very smooth surface morphology without any other nuclel or cracks.

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Effect of Buffer Layer and III/V Ratio on the Surface Morphology of Gan Grown by MBE

MRS Proceedings ◽

10.1557/proc-537-g3.77 ◽

1998 ◽

Vol 537 ◽

Cited By ~ 2

Author(s):

E. C. Piquette ◽

P. M. Bridger ◽

R. A. Beach ◽

T. C. McGill

Keyword(s):

Surface Morphology ◽

Buffer Layer ◽

Flux Ratio ◽

Plasma Source ◽

Growth Conditions ◽

Nitrogen Plasma ◽

Layer Growth ◽

Buffer Layers ◽

Flat Surfaces ◽

Aln Buffer

AbstractThe surface morphology of GaN is observed by atomic force microscopy for growth on GaN and AlN buffer layers and as a function of III/V flux ratio. Films are grown on sapphire substrates by molecular beam epitaxy using a radio frequency nitrogen plasma source. Growth using GaN buffer layers leads to N-polar films, with surfaces strongly dependent on the flux conditions used. Flat surfaces can be obtained by growing as Ga-rich as possible, although Ga droplets tend to form. Ga-polar films can be grown on AlN buffer layers, with the surface morphology determined by the conditions of buffer layer deposition as well as the III/V ratio for growth of the GaN layer. Near-stoichiometric buffer layer growth conditions appear to support the flattest surfaces in this case. Three defect types are typically observed in GaN films on AlN buffers, including large and small pits and “loop” defects. It is possible to produce surfaces free from large pit defects by growing thicker films under more Ga-rich conditions. In such cases the surface roughness can be reduced to less than l nm RMS.

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