TEM studies of laterally overgrown GaN layers grown on non-polarsubstrates

Conference · Thu Jan 05 04:00:00 EST 2006

OSTI ID:920343

Liliental-Weber, Z; Ni, X; Morkoc, H

Transmission electron microscopy (TEM) was used to study pendeo-epitaxial GaN layers grown on polar and non-polar 4H SiC substrates. The structural quality of the overgrown layers was evaluated using a number of TEM methods. Growth of pendeo-epitaxial layers on polar substrates leads to better structural quality of the overgrown areas, however edge-on dislocations are found at the meeting fronts of two wings. Some misorientation between the 'seed' area and wing area was detected by Convergent Beam Electron Diffraction. Growth of pendeo-epitaxial layers on non-polar substrates is more difficult. Two wings on the opposite site of the seed area grow in two different polar directions with different growth rates. Most dislocations in a wing grown with Ga polarity are 10 times wider than wings grown with N-polarity making coalescence of these layers difficult. Most dislocations in a wing grown with Ga polarity bend in a direction parallel to the substrate, but some of them also propagate to the sample surface. Stacking faults formed on the c-plane and prismatic plane occasionally were found. Some misorientation between the wings and seed was detected using Large Angle Convergent Beam Diffraction.

• Research Organization: Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
• Sponsoring Organization: USDOE; AFOSR ISSA 06NE001
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 920343
• Report Number(s): LBNL--60794; BnR: 400403109
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COALESCENCE
DIFFRACTION
DISLOCATIONS
ELECTRON DIFFRACTION
SEEDS
STACKING FAULTS
SUBSTRATES
TRANSMISSION ELECTRON MICROSCOPY