Anti-Surfactant in III-Nitride Epitaxy –Quantum Dot Formation and Dislocation Termination–

Abstract

A new approach toward epitaxial growth of group III nitrides using an “anti-surfactant” is presented. Two unique phenomena, quantum dot formation and dislocation termination, were recognized using this approach. The presence of Si atoms as an anti-surfactant on (Al)GaN surfaces modified the nitride epitaxial growth kinetics. These phenomena appeared to be independent; however, the growth mechanisms indicated a common surface event, which included the formation of a monolayer thick Si–N mask (nano-mask) within the fractional coverage on the surface. The Si–N nano-mask influenced the morphology of the deposited GaN surface, i.e. quantum structures, and also contributed to the termination of threading dislocations in GaN films.

Inhomogeneous distribution of defect-related emission in Si-doped AlGaN epitaxial layers with different Al content and Si concentration

“…These results indicate that the mechanism of hillock evolution has at least two origins, namely relaxation of compressive strain in AlGaN epitaxial layers and structural changes induced by Si incorporation (such as an anti-surfactant effect or a nano-mask effect). 4,5 Figures 1(b) and 3(b) show panchromatic CL images of AlGaN epitaxial layers with different relative Al content and with different Si concentration taken at 80 K, respectively. The observation positions were identical to those in the corresponding SEM images.…”

“…2) at room temperature. It is well known that Si doping into an Al x Ga 1-x N epitaxial layer drastically changes its structural, electrical, and optical properties through phenomena, such as dislocation inclination, 3 nano-mask effect, 4,5 changes in electric conductivity, 6,7 cathodoluminescence (CL) intensity enhancement, 8 introduction of point defects, 9 and changes in optical polarization along with variation in strain state. 10,11 For the fabrication of high-efficiency devices, it is important to investigate in detail the effects of Si doping on AlGaN ternary alloys.…”

Defect reduction in nonpolar a-plane GaN films using in situ SiNx nanomask

“…The use of in-situ SiN x interlayer has proven to be an effective technique in defect reduction in conventional c-plane GaN. [11][12][13] In this letter, we report on the use of insitu SiN x nanomask for defect reduction in a-plane GaN films. The simplicity of an in-situ defect reduction growth method is highly attractive.…”

Study on ECR dry etching and selective MBE growth of AlGaN/GaN for fabrication of quantum nanostructures on GaN (0001) substrates

“…Several groups [1][2][3] have reported the growth of GaN quantum dots using the anti-surfactant or Stranski-Krastanov (SK) effects. However, position-and size-controllability is rather poor in these growth modes.…”