VENNEGUES , P.

The microstructure of (11‐20) GaN films grown on (1‐102) sapphire substrates is studied by transmission electron microscopy. The predominant defects emerging at the surface of a 1‐2 μm thick layers are basal stacking faults of I1 type (1/6<20‐23> displacement vector). These defects are either terminated in the films by partial dislocations with...

Thanks to close crystalline structures and low lattice mismatches, nonpolar (11 (2) over bar0) 6H-SiC is expected to be a well- adapted substrate for the growth of nonpolar (11 (2) over bar0) III-nitride films. We demonstrate that the local reproduction of the basal planes stacking induces the presence of numerous planar defects (1.3 x 10(6)...

Thanks to close crystalline structures and low lattice mismatches, nonpolar (11 (2) over bar0) 6H-SiC is expected to be a well- adapted substrate for the growth of nonpolar (11 (2) over bar0) III-nitride films. We demonstrate that the local reproduction of the basal planes stacking induces the presence of numerous planar defects (1.3 x 10(6)...

The relaxation mechanisms in metal-organic vapor phase epitaxy grown (Al,Ga)N∕GaN heterostructures are studied. The first stage of the relaxation process is a two-dimensional–three-dimensional growth transition with the formation of mesalike islands separated by V-shaped trenches. The tensile stress relief is obtained by an elastic relaxation...

Strain relaxation mechanisms in metal-organic vapour phase epitaxy grown (Al,Ga)N/GaN heterostructures are presented. Relaxation first occurs through a 2D–3D transition. For pure AlN, misfit a-type dislocations are introduced at the coalescence front of growth islands. For (Al,Ga)N (Al concentration≤70%), the second relaxation step is cracking....

We report on the synthesis of new nitride-based compound by using annealing of AlN heteroepitaxial layers under a Si-atmosphere at temperatures between 1350°C and 1550°C. The structure and stoichiometry of this compound are investigated by high-resolution scanning transmission electron microscopy (HRSTEM), energy dispersive X-Ray (EDX)...

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New conditions for one‐step ELO were implemented to grow coalesced (11equation image0) non‐polar and (11equation image2) semi‐polar GaN layers starting, respectively, from R ‐ and M ‐plane sapphire. A great part of the stacking faults (SFs) and dislocations are filtrated resulting in GaN material with better structural and optical properties....