Title :
Characterization of dislocations and surface potential in III-V nitride heterostructures
Author :
Koley, G. ; Smart, J. ; Shealy, J.R. ; Spencer, M.G.
Author_Institution :
Dept. of Electr. & Comput. Eng., Cornell Univ., Ithaca, NY, USA
Abstract :
The characterization of III-V nitrides by Electrostatic Force Microscopy (EFM) and Atomic Force Microscopy (AFM) is reported. The samples studied consist of Aluminum Gallium Nitride/Gallium Nitride (Al xGa1-xN/GaN) heterostructures grown by Metal Organic Chemical Vapor Deposition (MOCVD) on sapphire substrate. The Al concentration and the thickness of the top layer of the heterostructure (AlxGa1-xN) have been varied in this study. The morphology of the surfaces was determined by AFM, while EFM performed in conjunction with AFM was used to measure the surface barrier potential. The surfaces of these heterostructures show regular step flow growth pinned by dislocations (present in concentrations of 108-10 9 cm-2). The surface potential variation around the dislocations have been observed to be of 0.1-0.3 V and having a FWHM (as determined by EFM) of 100-200 nm
Keywords :
III-V semiconductors; MOCVD coatings; aluminium compounds; atomic force microscopy; dislocation structure; gallium compounds; interface structure; semiconductor heterojunctions; surface energy; surface potential; wide band gap semiconductors; 0.1 to 0.3 V; 100 to 200 nm; Al concentration; AlxGa1-xN/GaN; AlGaN-GaN; Atomic Force Microscopy; Electrostatic Force Microscopy; III-V nitride heterostructures; MOCVD; dislocations; regular step flow growth; sapphire substrate; surface morphology; surface potential; surface potential variation; thickness; Aluminum gallium nitride; Atomic force microscopy; Atomic layer deposition; Chemical vapor deposition; Electrostatics; Gallium nitride; III-V semiconductor materials; MOCVD; Organic chemicals; Surface morphology;
Conference_Titel :
High Performance Devices, 2000. Proceedings. 2000 IEEE/Cornell Conference on
Conference_Location :
Ithaca, NY
Print_ISBN :
0-7803-6381-7
DOI :
10.1109/CORNEL.2000.902539
