Dislocation reduction in GaN with multiple MgxNy∕GaN buffer layers by metal organic chemical vapor deposition

2007 ◽  
Vol 90 (21) ◽  
pp. 212109 ◽  
Author(s):  
C. J. Tun ◽  
C. H. Kuo ◽  
Y. K. Fu ◽  
C. W. Kuo ◽  
C. J. Pan ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Buffer Layers ◽  
Organic Chemical ◽  
Dislocation Reduction ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

Polarity Control of GaN Films Grown by Metal Organic Chemical Vapor Deposition on (0001) Sapphire Substrates

2004 ◽  
Vol 831 ◽  
Author(s):  
Seiji Mita ◽  
Ramon Collazo ◽  
Raoul Schlesser ◽  
Zlatko Sitar
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Buffer Layers ◽  
Organic Chemical ◽  
Sapphire Substrates ◽  
Mixed Polarity ◽  
Metal Organic ◽  
Aln Buffer ◽  
Organic Chemical Vapor Deposition

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.

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