Evaluation of threading dislocation densities in In- and N-face InN

Abstract

The threading dislocation ͑TD͒ structure and density has been studied in In-and N-face InN films grown on GaN by plasma-assisted molecular beam epitaxy. The TD densities were determined by nondestructive x-ray diffraction rocking curve measurements in on-axis symmetric and off-axis skew symmetric geometries and calibrated by transmission electron microscopy measurements. TD densities were dominated by edge-type TDs with screw-component TDs accounting for less than 10% of the total TD density. A significant decrease in edge-type TD density was observed for In-face InN films grown at increasingly higher substrate temperatures. In-face InN films grown with excess In exhibited lower TD densities compared to films grown under N-rich conditions. The edge-type TD density of N-face InN films was independent of substrate temperature due to the higher allowable growth temperatures for N-face InN compared to In-face InN. TD densities in In-face InN also showed a strong dependence on film thickness. Films grown at a thickness of less than 1 m had higher TD densities compared with films grown thicker than 1 m. The lowest measured TD density for an In-face InN film was ϳ1.5ϫ 10 10 / cm 2 for 1 m thick films.

Thermoelectric properties of In-rich InGaN and InN/InGaN superlattices

“…We associate these pits to open core screw-component TDs, according to their very similar density observed in InN-based heteroepitaxial films on GaN. 44 Due to the deep surface pits the root-mean-square (rms) roughness of the as-grown SL structure amounts to ∼8 nm over the given AFM scan area.…”

Microstructure of PAMBE-grown InN layers on Si(111)

“…This process was suggested in Ref. [23] to be responsible for the majority of threading dislocations due to slight misorientations of the growth islands. In this sense, it is surprising that the FWHM of P350 exceeds the value of P325.…”

Investigation on HT-AlN Nucleation Layers and AlGaN Epifilms Inserting LT-AlN Nucleation Layer on C-Plane Sapphire Substrate

“…As we know, the strain along the growth direction is found to be tensile as elasticity theory predicts in the case of biaxial stress [15][16][17][18]. By comparison to the number of V-shaped pits, more tensile strain can be relieved in the condition of more V-shaped pits on the surface of Sample B.…”