Correlation Between Resistivity and Yellow Luminescence Intensity of MOCVD-Grown GaN Layers

2005 ◽  
Vol 892 ◽  
Author(s):  
Akihiro Hinoki ◽  
Yuichi Hiroyama ◽  
Tadayoshi Tsuchiya ◽  
Tomoyuki Yamada ◽  
Masayuki Iwami ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Leakage Current ◽  
Luminescence Intensity ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Clear Correlation ◽  
Yellow Luminescence ◽  
Metal Organic ◽  
Uv Lamp ◽  
Gan Buffer Layer

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.

Improved Resistivity of GaN with Partially Mg-Doped Grown on Si(111) Substrates by MOCVD

2012 ◽  
Vol 442 ◽  
pp. 16-20
Author(s):  
Yong Wang ◽  
Nai Sen Yu ◽  
Ming Li ◽  
Kei May Lau
Keyword(s):  
Surface Morphology ◽  
Buffer Layer ◽  
Chemical Vapor ◽  
High Resistivity ◽  
Organic Chemical ◽  
Good Surface ◽  
Metal Organic ◽  
Dc Current ◽  
Gan Buffer Layer ◽  
Mg Doped

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.

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
Keyword(s):  
Buffer Layer ◽  
Lattice Mismatch ◽  
Critical Role ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Force Microscopy ◽  
Mocvd Growth ◽  
Metal Organic ◽  
Aln Buffer ◽  
Gan Buffer Layer

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.

δ-Nb-doping Effect to The Interface Between IrO2 Top Electrode and Pb(Zr, Ti)O3 by Metal Organic Chemical Vapor Deposition

2004 ◽  
Vol 830 ◽  
Author(s):  
Osamu Matsuura ◽  
Hideki Yamawaki ◽  
Masaki Nakabayashi ◽  
Yoshimasa Horii ◽  
Yoshihiro Sugiyama
Keyword(s):  
Leakage Current ◽  
Low Voltage ◽  
Chemical Vapor ◽  
Doping Effect ◽  
Organic Chemical ◽  
Electrical Characteristics ◽  
Positive Direction ◽  
Metal Organic ◽  
Nb Doping ◽  
Organic Chemical Vapor Deposition

ABSTRACTWe studied the Nb doping effect on the electrical characteristics of MOCVD-PZT capacitors using uniformly Nb-doped Pb(Zr, Ti)O3 (UND-PZT) and δ-Nb-doped PZT (DND-PZT) prepared by MOCVD. The 2Pr for UND-PZT was small and the UND-PZT hysteresis shifted in a positive direction. However, the 2Pr for DND-PZT decreased by only 5.5% and the hysteresis of DND-PZT didn't shift. In addition, the leakage current of DND-PZT decreased by one order at low bias compared to non-doped PZT, because the δ-Nb-doping layer maintains the barrier height, higher than that of none-doped PZT due to defect compensation. As a result, Nb1% DND-PZT was well suited to use Nb doping which decreases leakage current at low voltage and maintains 2Pr.

Influence of the self-buffer layer on ZnO film grown by atmospheric metal organic chemical vapor deposition

2006 ◽  
Vol 515 (4) ◽  
pp. 1527-1531 ◽  
Author(s):  
Jinzhong Wang ◽  
Vincent Sallet ◽  
Gaëlle Amiri ◽  
Jean-François Rommelluere ◽  
Alain Lusson ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Buffer Layer ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
The Self ◽  
Organic Chemical ◽  
Zno Film ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

A Study on Impact of Process Parameters to Metal Organic Chemical Vapor Deposition Grown (002) Zinc Oxide Thin Films, at 320°C

2002 ◽  
Vol 744 ◽  
Author(s):  
Yuneng Chang ◽  
Hengchuan Lu ◽  
Yumeng Hung ◽  
Chunsung Lee ◽  
Jianming Chen ◽  
...  
Keyword(s):  
Growth Rate ◽  
Water Vapor ◽  
Buffer Layer ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Zno Films ◽  
Key Factors ◽  
Si Substrates ◽  
Metal Organic ◽  
Zno Buffer Layer

ABSTRACTThis paper reports preparation of highly oriented (002) ZnO films by atmospheric pressure CVD at 320°C, which is far below previous reported values. In this study, a cold wall horizontal system was used to thermally decompose sublimed zinc acetylacetonate (Zn(acac)2, Zn(C5H702)2) vapor, and reacted with water vapor to produce ZnO films at temperatures above 320°C. Through experimental data, we discovered that low deposition temperature, using water vapor as co-reactant and substrates with ZnO buffer layer pre-coated by PVD are the key factors to prepare (002) ZnO films. By using Si(100) pre-coated with sputtered ZnO amorphous buffer layer as substrates, the ZnO growth rate is highest. While using copper oxide pre-coated Si substrates gave the lowest growth rate, and deposited ZnO film is amorphous. Considering influence of CVD co-reactant, using Zn(acac)2 and water vapor gives higher growth rate and better crystallinity than CVD using Zn(acac)2 and oxygen. Water vapor may supply hydrogen to react with released acetylacetonyl ligand (C5H7O2), and help the formation of stable acetylaceton (C5H8O2) molecule. DPA shows that film contain 46% O and 54% Zn. XPS of Zn Auger identified the valence of Zn being Zn2+. It seems that excessive Zn might present as discrete Zn2+ dispersed between ZnO lattices.

Interface Quality and Electrical Performance of Low-Temperature Metal Organic Chemical Vapor Deposition Aluminum Oxide Thin Films for Advanced CMOS Gate Dielectric Applications

2002 ◽  
Vol 745 ◽  
Author(s):  
Spyridon Skordas ◽  
Filippos Papadatos ◽  
Steven Consiglio ◽  
Eric Eisenbraun ◽  
Alain Kaloyeros
Keyword(s):  
Dielectric Constant ◽  
Leakage Current ◽  
Gate Dielectric ◽  
Chemical Vapor ◽  
Oxide Semiconductor ◽  
Electrical Performance ◽  
Organic Chemical ◽  
Si Substrates ◽  
Annealing Conditions ◽  
Metal Organic

ABSTRACTIn this work, the electrical performance and interfacial characteristics of MOCVD-grown Al2O3 films are evaluated. Electrical characteristics (dielectric constant, leakage current) of as-deposited and annealed capacitor metal-oxide-semiconductor (MOS) stacks were determined using capacitance-voltage (C-V) and current-voltage (I-V) measurements. It was observed that the electrical properties were dependent upon specific annealing conditions, with an anneal in O2 followed by forming gas being superior with respect to leakage current, resulting in leakage characteristics superior to those of SiO2. All annealing conditions evaluated led to an increase in dielectric constant from 6.5 to 9.0–9.8. Also, Al2O3 growth and interfacial oxide growth characteristics on oxynitride/Si and Si substrates were evaluated and compared using spectroscopic ellipsometry. A parasitic oxide layer was observed to form on silicon during the initial stages of MOCVD Al2O3 growth, while a thin oxynitride layer deposited on Si prevented the growth of interfacial oxide.

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