Deformation-induced dislocations in 4H-SiC and GaN

Conference · Thu Jul 01 04:00:00 EDT 1999

OSTI ID:20104737

Hong, M H; Samant, A V; Orlov, V; Farber, B; Kiseielowski, C; Pirouz, P

Bulk single crystals of 4H-SiC have been deformed in compression in the temperature range 530--1,300 C, whereas a GaN thin film grown on a (0001) sapphire substrate was deformed by Vickers indentation in the temperature range 25--800 C. The TEM observations of the deformed crystals indicate that deformation-induced dislocations in 4H-SiC all lie on the (0001) basal plane but depending on the deformation temperature, are one of two types. The dislocations induced by deformation at temperatures above {approximately} 1,100 C are complete, with a Burgers vector, b, of 1/3 <11{bar 2}0> but are all dissociated into two 1/3 <10{bar 1}0> partials bounding a ribbon of stacking fault. On the other hand, the dislocations induced by deformation in the temperature range 550 < T < {approximately}1,100 C were predominantly single leading partials each dragging a stacking fault behind them. From the width of dissociated dislocations in the high-temperature deformed crystals, the stacking fault energy of 4H-SiC has been estimated to be 14.7 {+-} 2.5 mJ/m{sup 2}. Vickers indentations of the [0001]-oriented GaN film produced a dense array of dislocations along the three <11{bar 2}0> directions at all temperatures. The dislocations were slightly curved with their curvature increasing as the deformation temperature increased. Most of these dislocations were found to have a screw nature with their b parallel to <11{bar 2}0>. Also, within the resolution of the weak-beam method, they were not found to be dissociated. Tilting experiment show that these dislocations lie on the {l_brace}1{bar 1}00{r_brace} prism plane rather than the easier (0001) glide plane.

• Research Organization: Case Western Reserve Univ., Cleveland, OH (US)
• Sponsoring Organization: Department of Energy; Silicon Carbide Consortium
• DOE Contract Number: FG02-93ER45496
• OSTI ID: 20104737
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
DEFORMATION
DISLOCATIONS
EXPERIMENTAL DATA
GALLIUM NITRIDES
HYDROGEN ADDITIONS
SILICON CARBIDES