Influence of the Strain of AlN Buffer Layer on the Strain Evolution of GaN Epilayer Grown on 3-in 6H-SiC Substrate

2011 ◽  
Vol 335-336 ◽  
pp. 1242-1245
Author(s):  
Yu Long Fang ◽  
Jia Yun Yin ◽  
Zhi Hong Feng

The influence of the strain of AlN buffer layers on the strain evolution of GaN epilayers grown on 3-in 6H-SiC substrates by metal-organic chemical vapor deposition was investigated by double-crystal X-ray diffractometry, and Raman scattering spectra. It was found that the tensile strain of the GaN epilayers mainly decreases with the strain of the AlN buffer layers varied from tensile to compressive. A model based on the strain evolution during the epitaxial growth is proposed to provide a valuable reference for the massive production of large scale and high quality GaN epilayers.

2004 ◽  
Vol 831 ◽  
Author(s):  
Seiji Mita ◽  
Ramon Collazo ◽  
Raoul Schlesser ◽  
Zlatko Sitar

ABSTRACTThe polarity control of GaN films grown on c-plane sapphire substrates by low pressure metal organic chemical vapor deposition (MOCVD) was achieved by using N2 as a diluent and transport gas. The type of polarity was governed by the substrate treatment prior to the GaN growth. N-face (-c) GaN films were only obtained by pre-nitridation of the sapphire substrate after a H2 anneal, while Ga-face (+c) GaN films were grown directly on the substrates or on properly annealed AlN buffer layers. In addition, GaN films on improperly annealed AlN buffer layers, that is, under- or over-annealed buffer layers, yielded films with mixed polarity. Smooth N-face GaN films with 2.5 nm RMS roughness, as determined by atomic force microscopy (AFM), were obtained with shorter nitridation times (less than 2 min). Wet chemical etching in an aqueous solution of potassium hydroxide (KOH) was used to determine the polarity type.


2018 ◽  
Vol 6 (7) ◽  
pp. 1642-1650 ◽  
Author(s):  
Wenliang Wang ◽  
Yunhao Lin ◽  
Yuan Li ◽  
Xiaochan Li ◽  
Liegen Huang ◽  
...  

High-quality GaN-based light-emitting diode (LED) wafers have been grown on Si substrates by metal–organic chemical vapor deposition by designing epitaxial structures with AlN/Al0.24Ga0.76N buffer layers and a three-dimensional (3D) GaN layer.


2001 ◽  
Vol 680 ◽  
Author(s):  
Marco Schowalter ◽  
Brigitte Neubauer ◽  
Andreas Rosenauer ◽  
Dagmar Gerthsen ◽  
Oliver Schön ◽  
...  

ABSTRACTTransmission electron microscopy (TEM) has been applied to analyze the thickness and the In-concentration of InGaN layers in GaN/InGaN/GaN- and AlGaN/InGaN/AlGaN-quantum well (QW) structures. Two series of samples were grown by metal organic chemical vapor deposition varying either only the growth duration for the InGaN QW or by changing the Al- concentration in the buffer layers at unaltered InGaN growth conditions. A rising average In- concentration from 6.5 to 15.4 % and a decreasing growth rate are observed with increasing growth duration. The increase of the Al-concentration in the buffer layers from 0 to 36 % strongly affects the In-incorporation during the InGaN growth, which decreases from 17.5 to 2.5 %. All samples are characterized by an inhomogeneous In-distribution containing In-rich agglomerates with a size of only a few nanometers and less pronounced composition fluctuations on a scale of 100 nm.


Author(s):  
Chulsoo Byun ◽  
Dae Hyeon Kim ◽  
Kang Woo Joo ◽  
Kwang-Sun Kim

The metal organic chemical vapor deposition (MOCVD) process is widely used to form a multi-layered structure with thin films for diverse semiconductor materials. The MOCVD process is the most promising method for manufacturing chips that are based on the compound semiconductor, but its technology is partly still insufficient. If a device, for example, lacks a non-uniformity related to the composition and thickness of the film, it decreases the reliability of the final product and affects the economics. To ensure that the equipment is competitive in the worldwide markets, a high reliability including the controllability of compositions is required for the equipment. In this study the CFD analysis was used to investigate the behavior of the process gas in a MOCVD reactor where the process gases including the component of the GaN films are injected as separated through a multi-module showerhead for eventually targeting multi-component films such as AlGaInN materials. After applying of Porous Media, a stabilization of process gas was confirmed from the results of pressure distribution.


1995 ◽  
Vol 415 ◽  
Author(s):  
D.B. Studebaker ◽  
G. Doubinina ◽  
J. Zhang ◽  
Y.Y. Wang ◽  
V.P. Dravid ◽  
...  

ABSTRACTHigh temperature superconducting Yba2Cu3O7−x films were grown by liquid delivery metal-organic chemical vapor deposition (LDMOCVD) on silver-coated stainless steel substrates. The films are c-axis oriented, and exhibit a very low surface resistance of 110 μΩ at 77 K and 3 GHz. A two-step LDMOCVD method for growth of oriented (200) CeO2 films on amorphous substrates was also developed. Films of CeO2 for YBCO buffer layers were grown on fused silica (SiO2), polycrystalline alumina (Al2O3), and sapphire (A12O3). A highly c-axis oriented film of YBCO was grown on a fused silica substrate with a CeO2 buffer layer.


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