Seoul, South Korea
Seoul, South Korea

Time filter

Source Type

Kim J.Y.,Sunchon National University | Kim J.Y.,LumiGNtech Co. | Kim J.-K.,Sunchon National University | Kim J.-Y.,Korea Photonics Technology Institute | And 3 more authors.
Thin Solid Films | Year: 2013

Ag-embedded indium tin oxide (ITO) films were deposited on Corning 1737 glass by radio-frequency magnetron sputtering under an Ar or Ar/O2 mixed gas ambient with a combination of ITO and Ag targets that were sputtered alternately by switching on and off the shutter of the sputter gun. The effects of a subsequent surface treatment using H2 and H2 + O 2 mixed gas plasma were also examined. The specific resistance of the as-deposited Ag-embedded ITO sample was lower than that of normal ITO. The transmittance was quenched when Ag was incorporated in ITO. To enhance the specific resistance of Ag-embedded ITO, a surface treatment was conducted using H2 or H2 + O2 mixed gas plasma. Although all samples showed improved specific resistance after the H2 plasma treatment, the transmittance was quenched due to the formation of agglomerated metals on the surface. The specific resistance of the film was improved without any deterioration of the transmittance after a H2 + O2 mixed gas plasma treatment. © 2013 Elsevier B.V.


Lee H.-Y.,LumiGNtech Co. | Choi Y.-J.,LumiGNtech Co. | Kim J.-H.,LumiGNtech Co. | Jang H.-S.,LumiGNtech Co. | And 4 more authors.
Physica Status Solidi (C) Current Topics in Solid State Physics | Year: 2014

We are going to develop GaN growth process by HVPE method, which shows the near null value of free standing (FS)-GaN wafer bowing after laser lift-off (LLO) process in order to reduce the production cost of GaN substrate. The 309 to 318 μm thick HVPE grown GaN layers on sapphire shows 574 to 669 μm of as grown bows, and -299 to 95 μm of bow after LLO process. The 440 μm thick HVPE grown GaN layer on sapphire shows 693 μm of as grown bow, and -4 μm of bow after LLO process. From this GaN template, we could get the 356 μm thick FS-GaN wafer with 2 μm of bow after polishing. This GaN substrate shows at least 43.87 m of the radius of lattice curvature evaluated by 9-points measuring of (004) rocking curve along center line parallel to the main flat plane. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Kim J.Y.,Sunchon National University | Kim J.Y.,LumiGNtech Co. | Lee D.-M.,Sunchon National University | Kim J.-K.,Sunchon National University | And 2 more authors.
Applied Surface Science | Year: 2013

This study examined the effects of H2 and H2 + O 2 mixed gas plasma treatment on the properties of ITO films. The films were deposited on corning glass by RF magnetron sputtering under Ar and Ar/O2 mixed gas ambient. After a H2 plasma treatment, the ITO films showed an improved specific resistance due to the formation of oxygen vacancies acting as shallow donors, but showed quenched transmittance due to the formation of agglomerated metals on the surface. After an H2 + O2 mixed gas plasma treatment, the specific resistance of the film was improved without deteriorating transmittance. The enhanced specific resistance by mixed gas plasma treatment was attributed to the formation of free electrons by the incorporation of H in the lattice. © 2012 Elsevier B.V. All rights reserved.


Wang J.,Dong - Eui University | Ryu H.-B.,Dong - Eui University | Park M.-S.,Dong - Eui University | Lee W.-J.,Dong - Eui University | And 2 more authors.
Journal of Crystal Growth | Year: 2013

GaN epilayers were grown on Si(111) at 980 °C by a hydride vapor phase epitaxy (HVPE) method. AlxGa1-xN with thickness of ∼900 nm was inserted between Si substrate and GaN epilayer to act as a buffer layer. The investigation of the influence of different V/III ratios on GaN epilayer qualities reveals that high GaCl flow rate can increase the growth rate and improve the surface morphologies of GaN epilayers while high NH 3 flow rate is not good for reducing dislocations in GaN epilayers, which can be proved from the analysis of X-ray diffraction rocking curve (XRC), cross-sectional image of scanning electron microscopy (SEM) and image of atomic force microscopy (AFM). Finally, 1.22 μm GaN epilayer without cracks was successfully obtained with a three-step growth method. The surface roughness average (Ra) was measured to be 1.45 nm and the FWHM of GaN(0002) was 599 arcsec. The measured lattice constants for GaN epilayer were a=3.210 Å and c=5.177 Å, indicating the in-plane tensile stress and out-of-plane compressive stress of GaN epilayer. © 2012 Elsevier B.V. All rights reserved.


Oh H.-K.,LumiGNtech. Co. | Kim J.-G.,LumiGNtech. Co. | Hwang H.-H.,LumiGNtech. Co. | Choi Y.J.,LumiGNtech. Co. | And 4 more authors.
Physica Status Solidi (C) Current Topics in Solid State Physics | Year: 2010

We investigated the characterization of dislocations for GaN epilayers grown by HVPE and MOCVD methods through wet-chemical etching method, cathodoluminescence (CL) and high resolution X-ray diffraction (HR-XRD). The thickness of GaN epilayers grown by HVPE and MOCVD was prepared 15 μm and 5 μm, respectively. To evaluate etch pits density (EPD) of GaN epilayers by wet-chemical etching, samples were etched in molten KOH at 400 °C. The EPD for GaN grown by HVPE and by MOCVD was measured in close agreement with the respective dislocation density obtained by CL and HR-XRD. In case of GaN grown by HVPE, dislocation densities were 6.9×107/cm2 by EPD, 6.5×107/cm2 by CL, and 2.9×10 7/cm2 by HR-XRD. For GaN grown by MOCVD, dislocation density was 4.7x108/cm2 by EPD, 5.8×108/cm2 by CL, and 1.4x108/cm2 by HR-XRD. For GaN grown by MOCVD on patterned sapphire substrate, dislocation density was 1.0x108/cm 2 by EPD, 2.2×108/cm2 by CL and 7.2×107/cm2 by HR-XRD. Dislocation density of GaN grown by HVPE showed the lower value among these samples. Also we could expect that the wet-etching method at proper etching condition and time might be accurate determination method to investigate the dislocations in GaN epilayers. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.


Choi Y.J.,LumiGNtech Co. | Oh H.-K.,LumiGNtech Co. | Kim J.-G.,LumiGNtech Co. | Hwang H.-H.,LumiGNtech Co. | And 4 more authors.
Physica Status Solidi (C) Current Topics in Solid State Physics | Year: 2010

The warpage of the GaN template grown by a HVPE with gallium droplet treatment (GDT) was 13.8 μm, which was reduced by 80.3% of the warpage for GaN template grown by conventional MOCVD and 43% of the warpage for GaN template grown by HVPE without GDT. The treatment of gallium droplets on sapphire was achieved by thermal evaporator at room temperature. The E2 high peak of GaN template with GDT showed at 566.5 cm-1, whereas the E 2 high peak of GaN template by MOCVD positioned at 569.5 cm -1 in Raman scattering spectra. According to the frequency shifts of E2 high peak position for each template around 3 cm-1, the rellease of compressive stress of GaN template grown by HVPE with GDT was shown. In study of FE-SEM and Grow discharge spectroscopy (GDS), voids and concentration decline zones of gallium and aluminium in counter direction were formed at the interface between GaN epilayer and sapphire substrate during GaN growth by HVPE. We expected that the decrease of warpage and stress for GaN template with GDT could be caused by the formation of voids and concentration decline zones of gallium and aluminium. Etch pits density of GaN template with GDT was around 8.5×107/cm2. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.


Lee J.-S.,Korea University | Lee J.-S.,Korea Institute of Ceramic Engineering And Technology | Byun D.,Korea University | Oh H.-K.,LumiGNtech Co. | And 5 more authors.
Journal of Crystal Growth | Year: 2012

Growth of the Al xGa 1-xN ternary alloy using AlCl 3 and GaCl gases on sapphire substrate by hydride vapor phase epitaxy (HVPE) is presented in this study. Al xGa 1-xN epilayers were grown directly on sapphire substrate. To investigate the effect of growth temperature, we varied temperature from 1050 to 1090 °C at intervals of 20 °C. Some compositional non-uniformity was observed on the epilayer grown at 1050 °C from the results of UV-vis spectrophotometry, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Such a compositional non-uniformity disappeared with the increase of growth temperature and it was confirmed with the existence of Ga-rich islands shown by electron probe microanalysis (EPMA) compositional mapping. In addition, other characteristics such as surface roughness and crystallinity also improved with the increase of growth temperature and showed best results at 1090 °C. The Al composition of epilayer grown at 1090 °C was around 30%. © 2012 Elsevier B.V. All rights reserved.


Ha J.-H.,Dong - Eui University | Wang J.,Dong - Eui University | Lee W.-J.,Dong - Eui University | Choi Y.-J.,LumiGNtech Co. | And 3 more authors.
Journal of the Korean Physical Society | Year: 2015

The hydride vapor-phase epitaxy (HVPE) method was used to deposit high-quality InN layers on GaN inter-layer/sapphire (0001) structures that had been fabricated by using either the HVPE method or the metal-organic chemical-phase deposition (MOCVD) method. The effects of the group V/III ratio and different GaN inter-layers on the crystal quality of the InN layers were systemically investigated. The InN layer grown at a low Group V/III ratio revealed a high crystal quality with a two-dimensional (2D) growth mode. Also, the 110.7-nm-thick InN layer grown by using HVPE on a GaN inter-layer/sapphire (0001) substrate structure that had been fabricated by using MOCVD had a high crystal quality, with the full width at half maximum (FWHM) of the InN X-ray diffraction (XRD) peak being about 844 arcsec, and a smooth surface with an atomic force microscopy (AFM) roughness of about 0.07 nm. On the other hand, the 145.7-nm-thick InN layer grown by using HVPE on a GaN inter-layer/sapphire (0001) substrate structure that had been fabricated by using the HVPE method had a lower crystal quality, a FWHM value for the InN (0002) peak of about 2772 arcsec, and a surface roughness of about 3.73 nm. In addition, the peak of the E2 (high) phonon mode for the 110.7-nm-thick InN layer grown by using HVPE on a GaN inter-layer/sapphire (0001) structure that had been fabricated by using MOCVD was detected at 491 cm -1 and had a FWHM of 9.9 cm-1. As a result, InN layers grown by using HVPE on GaN inter-layer/sapphire (0001) substrate structures fabricated by using MOCVD have a high crystal quality and a reduced Raman value, which agrees well with the results of the XRD analysis. © 2015, The Korean Physical Society.


Patent
Lumigntech Co. | Date: 2012-10-21

The present invention is directed to a method of manufacturing a substrate, which includes loading a base substrate into a reaction furnace; forming a buffer layer on the base substrate; forming a separation layer on the buffer layer; forming a semiconductor layer on the separation layer at least two; and separating the semiconductor layer from the base substrate via the separation layer through natural cooling by unloading the base substrate from the reaction furnace.


Provided are a semiconductor substrate including an uneven structure disposed on a surface of a substrate, a buffer layer disposed on the uneven structure, the buffer layer having an acicular structure, a compound semiconductor layer disposed on the buffer layer to planarize the uneven structure, and a plurality of voids defined between the substrate and the compound semiconductor layer, and a method for manufacturing the same. Thus, since the acicular structure disposed on the uneven structure of the substrate forms the voids on an interface between the substrate and the single crystal GaN layer to relax a stress due to a lattice mismatch and intercept propagation of a breakdown potential, a warpage characteristic of the grown single crystal GaN layer may be reduced, as well as, crystallinity may be improved.

Loading LumiGNtech Co collaborators
Loading LumiGNtech Co collaborators