Optical and electrical characterizations of micro-LEDs grown on lower defect density epitaxial layers

This paper reports the progress of the thick epitaxy development at Dow Corning. Epiwafers with thickness of 50 – 100 m have been grown on 4° off-axis 76mm 4H SiC substrates. Smooth surface with RMS roughness below 1nm and defect density down to 2 cm-2 are achieved for 80 - 100 m thick epiwafers. Long carrier lifetime of 2 – 4 s are routinely obtained, and low BPD density in the range of 50 down to below 10 cm-2 is confirmed. High voltage JBS diodes have been successfully fabricated on these wafers with thick epitaxial layers.

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Electrical Characteristics of Crystalline Gd2O3 Film on Si (111): Impacts of Growth Temperature and Post Deposition Annealing

MRS Proceedings ◽

10.1557/proc-1252-i05-09 ◽

2010 ◽

Vol 1252 ◽

Author(s):

Gang Niu ◽

Bertrand Vilquin ◽

Nicolas Baboux ◽

Guillaume Saint-Girons ◽

Carole Plossu ◽

...

Keyword(s):

Molecular Beam ◽

Defect Density ◽

Oxide Thickness ◽

Electrical Characteristics ◽

Equivalent Oxide Thickness ◽

Optimal Temperature ◽

Post Deposition Annealing ◽

High K ◽

Electrical Characterizations ◽

Post Deposition

AbstractThis work reports on the epitaxial growth of crystalline high-k Gd2O3 on Si (111) by Molecular Beam Epitaxy (MBE) for CMOS gate application. Epitaxial Gd2O3 films of different thicknesses have been deposited on Si (111) between 650°C~750°C. Electrical characterizations reveal that the sample grown at the optimal temperature (700°C) presents an equivalent oxide thickness (EOT) of 0.73nm with a leakage current density of 3.6×10-2 A/cm2 at |Vg-VFB|=1V. Different Post deposition Annealing (PDA) treatments have been performed for the samples grown under optimal condition. The Gd2O3 films exhibit good stability and the PDA process can effectively reduce the defect density in the oxide layer, which results in higher performances of the Gd2O3/Si (111) capacitor.

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Growth and Characterization of High-Performance GaN and AlxGa1−xN Ultraviolet Avalanche Photodiodes Grown on GaN Substrates

MRS Proceedings ◽

10.1557/proc-1040-q03-03 ◽

2007 ◽

Vol 1040 ◽

Cited By ~ 1

Author(s):

Russell D. Dupuis ◽

Dongwon Yoo ◽

Jae-Hyun Ryou ◽

Yun Zhang ◽

Shyh-Chinag Shen ◽

...

Keyword(s):

Defect Density ◽

Growth Parameters ◽

Avalanche Photodiodes ◽

Chemical Vapor ◽

Device Fabrication ◽

Breakdown Field ◽

Structural Quality ◽

Epitaxial Layers ◽

Free Standing

AbstractWide-bandgap III-nitride-based avalanche photodiodes (APDs) are important for photodetectors operating in UV spectral region. For the growth of GaN-based heteroepitaxial layers on lattice-mismatched substrates such as sapphire and SiC, a high density of defects is introduced, thereby causing device failure by premature microplasma breakdown before the electric field reaches the level of the bulk avalanche breakdown field, which has hampered the development of III-nitride based APDs. In this study, we investigate the growth and characterization of GaN and AlGaN-based APDs on free-standing bulk GaN substrates. Epitaxial layers of GaN and AlxGa1−xN p-i-n ultraviolet avalanche photodiodes were grown by metalorganic chemical vapor deposition (MOCVD). Improved crystalline and structural quality of epitaxial layers was achieved by employing optimum growth parameters on low-dislocation-density bulk substrates in order to minimize the defect density in epitaxially grown materials. GaN and AlGaN APDs were fabricated into 30μm- and 50μm-diameter circular mesas and the electrical and optoelectronic characteristics were measured. APD epitaxial structure and device design, material growth optimization, material characterizations, device fabrication, and device performance characteristics are reported.

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Homo-Epitaxial Growth on 2° Off-Cut 4H-SiC(0001) Si-Face Substrates Using H2-SiH4-C3H8 CVD System

Materials Science Forum ◽

10.4028/www.scientific.net/msf.778-780.214 ◽

2014 ◽

Vol 778-780 ◽

pp. 214-217 ◽

Cited By ~ 5

Author(s):

Kentaro Tamura ◽

Chiaki Kudou ◽

Keiko Masumoto ◽

Johji Nishio ◽

Kazutoshi Kojima

Keyword(s):

Confocal Microscopy ◽

Epitaxial Growth ◽

Carrier Concentration ◽

Epitaxial Layer ◽

Defect Density ◽

Epitaxial Layers ◽

Differential Interference Contrast ◽

Step Bunching

We have grown epitaxial layers on 2° off-cut 4H-SiC(0001) Si-face substrates. The epitaxial layer surfaces on 2° off-cut substrates are more prone to generate step-bunching than on 4° off-cut substrates, which are observed by confocal microscopy with differential interference contrast. We have speculated that the step-bunching is generated at the beginning of an epitaxial growth. Triangular defect density of epitaxial layers on 2° off-cut substrates is as low as 0.7 cm–2 for the size corresponding to 150 mm. We have firstly reported distribution of 2° off-cut epitaxial layers for the 150-mm size using two 76.2-mm wafers: σ/mean = 3.3% for thickness, σ/mean = 7.3% for carrier concentration.

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Epitaxial Growth of SiC in a Vertical Multi-Wafer CVD System: Already Suited as Production Process?

MRS Proceedings ◽

10.1557/proc-572-149 ◽

1999 ◽

Vol 572 ◽

Cited By ~ 1

Author(s):

Roland Rupp ◽

Christian Hecht ◽

Arno Wiedenhofer ◽

Dietrich Stephani

Keyword(s):

Epitaxial Growth ◽

Gas Flow ◽

Defect Density ◽

Schottky Diodes ◽

Impurity Level ◽

Thickness Variation ◽

Epitaxial Layers ◽

Growth Step ◽

Low Leakage ◽

Low Leakage Current

ABSTRACTResults about a new CVD system suited for epitaxial growth on six 2 inch SiC-wafers at a time are presented. Excellent gas flow stability is achieved for this new reactor type as shown by in- situ observations of the gas flow dynamics in the reactor chamber. These experimental results agree favorably with numerical process simulation results.The epitaxial layers grown in the multi-wafer system so far show a by an order of magnitude higher background impurity level (≤1015 cm−3) as reported previously for layers grown in single-wafer systems by the authors and other groups (≤ 1014 cm−3). On the other hand, the doping homogeneity achieved until today is very encouraging. The variation on a 2 inch wafer is less than ± 20% at about 1*1016 cm−3. The wafer to wafer variation of the average doping value both within a run and from run to run is within 15 %. The reproducibility and uniformity of the layer thickness is even better (total thickness variation ≤5% on a 2 inch wafer). The surface of the epitaxial layers is very smooth with a typical growth step height of 0.5 nm (4H, 8° off orientation). First measurements on Schottky diodes build on these layers show low leakage current values indicating low point defect density in the epitaxial layers.

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Silicon Carbide Epitaxial Layers Grown ON SiC Wafers With Reduced Micropipe Density

MRS Proceedings ◽

10.1557/proc-512-131 ◽

1998 ◽

Vol 512 ◽

Cited By ~ 5

Author(s):

S. Rendakova ◽

N. Kuznetsov ◽

N. Savkina ◽

M. Rastegaeva ◽

A. Andreev ◽

...

Keyword(s):

Silicon Carbide ◽

High Power ◽

Small Area ◽

Defect Density ◽

Schottky Barriers ◽

Epitaxial Layers ◽

Power Devices ◽

Large Area ◽

Vacuum Sublimation ◽

Sublimation Method

ABSTRACTThe characteristics of SiC high-power devices are currently limited by the small area of the devices, which is usually less than 1 sq. mm. In order to increase device area, defect density in SiC epitaxial structures must be reduced. In this paper, we describe properties of silicon carbide epitaxial layers grown on 4H-SiC wafers with reduced micropipe density. These layers were grown by the vacuum sublimation method. Large area Schottky barriers (up to 8 mm2) were fabricated on SiC epitaxial layers and characterized.

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Growth of Epitaxial Layers of GexSi1−x BY UHV/CVD

MRS Proceedings ◽

10.1557/proc-198-527 ◽

1990 ◽

Vol 198 ◽

Author(s):

Marco Racanelli ◽

David W. Greve

Keyword(s):

Growth Rate ◽

Deposition Temperature ◽

Defect Density ◽

Epitaxial Films ◽

Epitaxial Layers ◽

Silicon Substrates ◽

Germanium Content ◽

Film Roughness

ABSTRACTUndoped epitaxial layers of GexSi1−x have been grown on (100) silicon substrates using the UHV/CVD technique. Epitaxial films were obtained at growth temperatures between 577 and 665 C. The growth rate and germanium content of the layers has been determined as a function of the germane flow and the deposition temperature. A bake at 800 C was found to be highly beneficial in reducing the defect density and improving the film roughness.

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Band Gap Engineering of Nano Scale AlGaN Epitaxial Layers by Swift Heavy Ion Irradiation

MRS Proceedings ◽

10.1557/proc-1181-dd13-10 ◽

2009 ◽

Vol 1181 ◽

Author(s):

SATHISH N ◽

Devaraju G ◽

Srinivasa Rao N ◽

Anand Pathak ◽

Andrzej Turos ◽

...

Keyword(s):

Optical Properties ◽

Defect Density ◽

Ion Irradiation ◽

Compressive Strain ◽

Heavy Ion ◽

High Energy ◽

Epitaxial Layers ◽

Algan Layer ◽

Before And After ◽

Energy Irradiation

AbstractEpitaxial AlGaN/GaN layers grown by MBE on SiC substrates were irradiated with 150 MeV Ag ions at a fluence of 5×1012 ions/cm2. AlGaN/GaN MQWs were grown on Sapphire substrate by MOCVD and irradiated with 200 MeV Au8+ ions at a fluence of 5×1011 ions/cm2 . These samples were used to study the effects of SHI on optical properties of AlGaN/GaN based nano structures. RBS/Channelling strain measurements were carried out at off normal axis of irradiated and unirradiated samples. In as grown samples, AlGaN layer is partially relaxed with a small compressive strain. After irradiation this compressive strain increases by 0.22% in AlGaN layer. Incident ion energy dependence of dechannelling parameter shows E1/2 dependence, which corresponds to the dislocations. Defect densities were calculated from the E1/2 graph. As a result of irradiation defect density increased on both GaN and AlGaN layer. Optical properties of AlGaN/GaN MQWs before and after irradiation have been analyzed using PL. This study shows that SHI increase the confinement effects in the MQWs and intensity of the active layer of the MQWs luminescence is increased by one order. This may be due to the induced strain in GaN and AlGaN layers. Some unwanted yellow luminescence has also been introduced by the SHI possibly due the point defects or defect luminescence from the induced dislocations in GaN bulk epitaxial layers. In this study, we present some new results concerning high energy irradiation on AlGaN/GaN heterostructures and MQWs characterized by RBS/Channelling and PL.

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Thick Epitaxial Layers Growth by Chlorine Addition

Materials Science Forum ◽

10.4028/www.scientific.net/msf.615-617.55 ◽

2009 ◽

Vol 615-617 ◽

pp. 55-60 ◽

Cited By ~ 13

Author(s):

Francesco La Via ◽

Gaetano Izzo ◽

Massimo Camarda ◽

Giuseppe Abbondanza ◽

Danilo Crippa

Keyword(s):

Growth Rate ◽

Defect Density ◽

Low Cost ◽

Schottky Diodes ◽

Epitaxial Layers ◽

Power Devices ◽

Particle Detectors ◽

Characterization Methods ◽

X Ray ◽

Very High

The growth rate of 4H-SiC epi layers has been increased up to 100 µm/h by chlorine addition. The epitaxial layers grown with this process have been characterized by electrical, optical and structural characterization methods. Very thick (> 100 µm) epitaxial layer has been grown and the Schottky diodes realized on these layers have good yield (> 87%) with a low defect density (10/cm2). This process gives the opportunity to realize very high power devices with breakdown voltages in the range of 10 kV or X-Ray and particle detectors with a low cost epitaxy process.

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Silicon Carbide Hot-Wall Epitaxy for Large-Area, High-Voltage Devices

MRS Proceedings ◽

10.1557/proc-1069-d04-01 ◽

2008 ◽

Vol 1069 ◽

Cited By ~ 6

Author(s):

Michael O'Loughlin ◽

K. G. Irvine ◽

J. J. Sumakeris ◽

M. H. Armentrout ◽

B. A. Hull ◽

...

Keyword(s):

Silicon Carbide ◽

Process Optimization ◽

High Voltage ◽

Defect Density ◽

Epitaxial Layers ◽

Power Devices ◽

Large Area ◽

Device Processing ◽

Defect Densities ◽

Hot Wall Epitaxy

ABSTRACTThe growth of thick silicon carbide (SiC) epitaxial layers for large-area, high-power devices is described. Horizontal hot-wall epitaxial reactors with a capacity of three, 3-inch wafers have been employed to grow over 350 epitaxial layers greater than 100 μm thick. Using this style reactor, very good doping and thickness uniformity and run-to-run reproducibility have been demonstrated. Through a combination of reactor design and process optimization we have been able to achieve the routine production of thick epitaxial layers with morphological defect densities of around 1 cm−2. The low defect density epitaxial layers in synergy with improved substrates and SiC device processing have resulted in the production of 10 A, 10 kV junction barrier Schottky (JBS) diodes with good yield (61.3%).

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