Characterization of the parasitic masking layer formed during GaN SA-MOVPE using PECVD SiO2 masks

• Published in: Applied surface science 2023-12, Vol.640, p.158325, Article 158325
• Main Authors: Stȩpniak, Michał, Owczarek, Sylwia, Szyszka, Adam, Wośko, Mateusz, Paszkiewicz, Regina
• Format: Article
• Language: English
• Subjects: AFM; Gallium nitride; Parasitic masking; PECVD; SCM; Selective epitaxy; SSRM; XPS
• ISSN: 0169-4332
• DOI: 10.1016/j.apsusc.2023.158325

X-ray photoelectron spectroscopy (XPS) was used to study the surface composition of the parasitic masking layer formed during selective area metalorganic vapor phase epitaxy (MOVPE) of gallium nitride (GaN) using silicon dioxide (SiO2) masks deposited by plasma enhanced chemical vapor deposition (PECVD). It was shown that non-stoichiometric silicon oxynitride layer (SiOxNy) is responsible for the inhibition of GaN nucleation in the vicinity of the SiO2 mask. Atomic force microscopy (AFM) was applied to examine the surface topography, whereas scanning capacitance microscopy (SCM) and scanning spreading resistance microscopy (SSRM) techniques were used for the purpose of electrical characterization of the parasitic masking layer. The overgrowth of GaN islands through the discontinuities in the SiOxNy film was shown. The SCM imaging showed the presence of a positive electric charge in the parasitic masking layer, indicating the accumulation of defects in the silicon oxynitride film. [Display omitted] •Parasitic substrate masking during SA-MOVPE of GaN using PECVD SiO2 mask is presented.•Surface topography of the deposition-free region is characterized.•A compound responsible for the adverse inhibition of GaN nucleation is identified.•Overgrowth of GaN islands through the discontinuities in the parasitic maskk is shown.•Accumulation of a positive electric charge in the parasitic mask is discussed.