Threading dislocation reduction in InN grown with in situ surface modification by radical beam irradiation

Abstract

In this study, the applicability of in situ surface modification by radical beam irradiation method to reduce threading dislocation density in InN was investigated. The dislocation behavior, crystallographic quality, electrical properties, and photoluminescence properties of InN grown with this method were studied. Transmission electron microscopy observation revealed that dislocation density in the InN layer reduced by a factor of 3 in certain regions and showed good agreement with the results from photoluminescence spectroscopy. If this technology is established, high-quality InN with low threading dislocation density can be achieved with a very simple and repeatable growth process.

Nitrogen Radical Beam Irradiation on InN Film for Surface Modification

“…This is in agreement with a previous report 12) which states that the mobility limitation factor of InN is the threading dislocations. We confirmed that the threading dislocation density of the InN template did not change after N radical beam irradiation 3) . In other words, although point defects increased due to N radical beam irradiation, there was no influence on the threading dislocation density; thus, the change in mobility was not considered to have occurred.…”

“…By applying N radical beam irradiation on the InN template before regrowing the InN film, the threading dislocations are bent, merged, and terminated at the regrowth interface, thereby reducing the threading dislocation density in the regrown layer 3) . However, the InN template surface modification by N radical beam irradiation has not been studied in more detail.…”

Repeatability and Mechanisms of Threading Dislocation Reduction in InN Film Grown with In Situ Surface Modification by Radical Beam Irradiation

“…Since threading dislocation density in InN template is high which is around 10 10 cm -2 15),16),30), 31) , merging of dislocations at the interface of the irradiated InN template and the regrown InN film could play the dominant role in the reduction of the dislocation density. We have confirmed by TEM that some dislocation merged at the regrowth interface and resulted in one single dislocation 19) .…”

“…At present, the common density of screw dislocation and edge dislocation in InN are around ~2×10 9 cm -2 and ~2×10 10 cm -2 , respectively 23) . Figure 3 However, compare to our previous result 19) , the screw dislocation was slightly bent at the regrowth interfaces and a few additional screw dislocations was generated at the From this result, it is suggested that in order to make use of the N radical irradiation process effectively, it is necessary to optimize the thickness of each InN layer during the N radical irradiation process.…”

“…When compare with our proposed method, the faceted surface morphology was not obtained on the irradiated InN template. On the other hand, the surface changed from atomically flat surface to threedimensional rough surface 19) . The surface morphological changes by N radical irradiation have also been reported by another groups 17),18) .…”