Characterization of an AlN buffer layer and a thick-GaN layer grown on sapphire substrate by MOCVD

Çörekçí, S.; Öztürk, Mustafa Kemal; Bengi, A.; Çakmak, M.; Özçelik, Süleyman; Özbay, Ekmel

doi:10.1007/s10853-010-4973-7

Cited by 15 publications

(7 citation statements)

References 54 publications

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“…In this study, InGaN/GaN/AlN epilayers are grown on sapphire that results with high dislocation density. In order to see defects caused from crystallity level and mosaic block structure Dedge and Dscrew type dislocation densities may be calculated wih equations ( 1) and (2) [7][8][9]. Table 3 shows edge, screw type dislocation densities.…”

Section: Resultsmentioning

confidence: 99%

“…Many researchers studied for minimising defects of them [5,6]. For example, defect analysis, tilt and twist angles, dislocation density values of layers are determined by using symmetric and asymmetric peak broadening [7,8]. In general, it is sufficient to determine full width at half maximum (FWHM) of a symmetric plane reflection.…”

Section: Mosaic Defect and Afm Study On Gan/alinn/aln/sapphire Hemt Structures 1 Introductionmentioning

confidence: 99%

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GaN/AlInN/AlN/Safir HEMT Yapılar için Mozaik Kusur ve AFM Çalışması

et al. 2022

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In this study, mosaic defect and detailed AFM investigation of GaN/AlInN/AlN/ Sapphire HEMT structure is made. Figure. 5 AFM images of samples A, B and C AimAim of this study is to investigate mosaic defects and morphological properties of GaN/AlInN/AlN/sapphire HEMT structure. Design & Methodology Samples in this study are grown by metal organic chemical vapor deposition technique and XRD and AFM investigation is made on them. OriginalityThis study is original because investigation of GaN/AlInN/AlN/Sapphire structure in such way is rare. FindingsIn this study dislocation density and surface properties of GaN/AlInN/AlN/sapphire structures are determined. ConclusionDislocation densities, RMS values and twist angles are in good accordance with optimisation order of samples.

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Section: Resultsmentioning

confidence: 99%

Section: Mosaic Defect and Afm Study On Gan/alinn/aln/sapphire Hemt Structures 1 Introductionmentioning

confidence: 99%

GaN/AlInN/AlN/Safir HEMT Yapılar için Mozaik Kusur ve AFM Çalışması

et al. 2022

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“…This is caused by inserting a LT AlN into the HT AlN layer, which prevents the propagation of cracks and defects from the first HT AlN layer to the top HT AlN layer . The top layer of the HLHT AlN buffer is formed with a high crystalline quality and a low defects density to promote the further growth of GaN . It has also been reported that intermediate temperature interlayer technique can markedly reduce the density of threading dislocations .…”

Section: Resultsmentioning

confidence: 99%

Barrier Strain and Carbon Incorporation‐Engineered Performance Improvements for AlGaN/GaN High Electron Mobility Transistors^**

Luong

Tran

et al. 2014

Chemical Vapor Deposition

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The improvements in electrical characteristics of AlGaN/GaN high electron mobility transistors (HEMTs) grown using metalorganic (MO)CVD by engineering structure, barrier strain, and unintentional carbon incorporation, are demonstrated in this work. Both normal HEMT structure (with a high temperature (HT) AlN buffer) and advanced HEMT structure (with a highlow-high temperature (HLHT) AlN buffer, and a HT AlN interlayer (IL)) present a breakdown voltage higher than 200 V, while a much smaller breakdown voltage of 17 V is measured on the conventional structure using a low-temperature GaN buffer. The HT AlN IL inserted in the middle of the conventional HEMT structure introduces a reduction in the tension of the AlGaN barrier, which results in an improvement of the surface morphology (0.46 nm). As a consequence, the two-dimensional electron gas (2DEG) mobility increases by remarkable 46% (1900 cm 2 V À1 s À1 ). The HLHT AlN buffer, substituting for the HT AlN buffer, leads to the enhancement of GaN crystalline quality, which contributes to the performance improvement for HEMTs. The advanced HEMT, using both an AlN IL and an HLHT AlN buffer, produces increases in the DC maximum drain current by 35.5% ($680 A mm À1 ), and in the transconductance by 15% (114 mS mm À1 ) in comparison with the normal HEMT with an AlN buffer. The very low leakage current in the advanced HEMTs is caused by optimizing the design of the buffer and modifying growth parameters. Lastly, the reduction of AlGaN barrier tensile strain by inserting the HT AlN IL is promising for an improvement in AlGaN/GaN HEMT reliability.

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“…InGaN, GaN and AlGaN layers are grown on c-(001)-oriented sapphire substrate. Before the epitaxial growth operation, sapphire substrate is exposed to temperature of 1100 °C in nitrogen atmosphere for 10 min to remove the oxide layer on the surface of it [8,9]. Trimethylgallium (TMGa), trimethylaluminum (TMAl), trimethylindium (TMIn) and ammonia (NH 3 ) compound chemical reactions are gained from Ga, Al, In and N sources, respectively.…”

Section: Methodsmentioning

confidence: 99%

On the elastic properties of INGAN/GAN LED structures

et al. 2019

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In this study, three InGaN/GaN light-emitting diode (LED) structures with five periods are investigated grown by metal organic chemical vapor deposition (MOCVD) technique. During growth of these three samples, active layer growth temperatures are adjusted as 650, 667 and 700 °C. These structures are grown on sapphire (Al 2 O 3 ) wafer as InGaN/GaN multiquantum wells (MQWs) between n-GaN and p-AlGaN + GaN contact layers. During growth, pressure and flux ratio of all sources are kept constant for all samples. Only temperature of InGaN active layer is changed. These structures are analyzed with high-resolution X-ray diffraction (HR-XRD) technique. Their surface morphologies are investigated with atomic force microscopy (AFM). Reciprocal space mapping (RSM) is made different from classical HR-XRD analyses. Using this method, mixed peaks belonging to InGaN, AlGaN and GaN layers are seen more clearly and their full width at half maximum (FWHM) values is determined with better accuracy. With FWHM gained from RSM and Williamson-Hall (W-H) method based on universal elastic coefficients of the material, particle size D (nm), uniform stress σ (GPa), strain ε and anisotropic energy density u (kJ m −3 ) parameters for the samples are calculated. The results are compared with literature. On the other hand, to have an idea about the accuracy of the results AFM images are examined. Parameters calculated showed differences but it is seen that the largest particle size is gained for GaN and the smallest is gained for AlGaN. For all parameters, it is seen that they increase for GaN layer and decrease for AlGaN layer with increasing temperature. For InGaN layer parameters, they showed both increasing and decreasing or decreasing and increasing behavior harmonically with an increase in temperature. Results showed that they are compatible with literature. Results gained from Scherrer and W-H are very near to each other.

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Characterization of an AlN buffer layer and a thick-GaN layer grown on sapphire substrate by MOCVD

Cited by 15 publications

References 54 publications

GaN/AlInN/AlN/Safir HEMT Yapılar için Mozaik Kusur ve AFM Çalışması

GaN/AlInN/AlN/Safir HEMT Yapılar için Mozaik Kusur ve AFM Çalışması

Barrier Strain and Carbon Incorporation‐Engineered Performance Improvements for AlGaN/GaN High Electron Mobility Transistors^**

On the elastic properties of INGAN/GAN LED structures

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Characterization of an AlN buffer layer and a thick-GaN layer grown on sapphire substrate by MOCVD

Cited by 15 publications

References 54 publications

GaN/AlInN/AlN/Safir HEMT Yapılar için Mozaik Kusur ve AFM Çalışması

GaN/AlInN/AlN/Safir HEMT Yapılar için Mozaik Kusur ve AFM Çalışması

Barrier Strain and Carbon Incorporation‐Engineered Performance Improvements for AlGaN/GaN High Electron Mobility Transistors**

On the elastic properties of INGAN/GAN LED structures

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Barrier Strain and Carbon Incorporation‐Engineered Performance Improvements for AlGaN/GaN High Electron Mobility Transistors^**