The data set for the article contains secondary electron images, backscatter electron using a scanning electron microscope. The dataset contains data acquired from a (11-22) semi-polar GaN thin film overgrown on regularly arrayed GaN micro-rod array templates grown by metal organic vapour phase epitaxy. Figure numbers in the data file descriptions refer to the Journal of Applied Physics paper by Naresh Kumar et al. (2018) referenced in the related publications section.
Figures 1 and 2 are schematic of the sample and the experimental setup.
Figure 3 is ECCI acquired in the forescatter geometry showing individual dislocations as well as clustering of threading dislocations in a periodic fashion. The periodicity of the clustering is due to the underlying micro-rod template.
Figure 4: ECCI acquired in the forescatter geometry revealing basal plane stacking faults (BSFs) (a) Bright lines corresponding to BSFs showing contrast reversal as seen in (b).
Figure 5. (a) SE image showing topography and (b) ECCI showing BSFs, the sample is not tilted (proper backscattered geometry). Please note both the images are from the same area.
Figure 6. Plan view TEM image acquired using a g = (10-10) with the specimen viewed along the [-1-120] revealing basal plane stacking faults.
Taking advantage of electron diffraction based measurements, in a scanning electron microscope, can deliver non-destructive and quantitative information on extended defects in semiconductor thin films. In the present work, we have studied a (11-22) semi-polar GaN thin film overgrown on regularly arrayed GaN micro-rod array templates grown by metal organic vapour phase epitaxy. We were able to optimise the diffraction conditions to image and quantify basal plane stacking faults (BSFs) and threading dislocations (TDs) using electron channelling contrast imaging (ECCI). Clusters of BSFs and TDs were observed with the same periodicity as the underlying micro-rod array template. The average BSF and TD density was estimated to be ≈ 4 × 104 cm-1 and ≈ 5 × 108 cm-2 respectively. The contrast seen for BSFs in ECCI is similar to that observed for plan-view transmission electron microscopy images, with the only difference being the former acquires the backscattered electrons and latter collects the transmitted electrons. Our present work shows the capability of ECCI for quantifying extended defects in semi-polar nitrides and represents a real step forward for optimising the growth conditions in these materials.