Freestanding patterned polycrystalline GaN substrate by a straightforward and affordable technique. (December 2018)

• Record Type: Journal Article
• Authors: Zainal, N.; Samsudin, M.E.A.; Taib, Muhamad Ikram Md; Ahmad, M.A.; Ariff, A.; Alwadai, N.; Roqan, I.S.
• Is Part Of: Materials science in semiconductor processing. Volume 88(2018)
• Page Start: 40
• Page End: 44
• Publication Date: 2018-12
• Subjects: Semiconductors -- Periodicals; Integrated circuits -- Materials -- Periodicals; Semiconducteurs -- Périodiques; Circuits intégrés -- Matériaux -- Périodiques; Electronic journals; 621.38152
• DOI: 10.1016/j.mssp.2018.07.029
• Languages: English
• ISSNs: 1369-8001

Abstract

Abstract: A new process for producing a freestanding patterned polycrystalline GaN substrate by applying a straightforward and affordable technique is presented here. Such substrate was fabricated by depositing ~ 50 µm thick bulk GaN layer on porous Si/Si substrate by e-beam evaporator with successive ammonia annealing to improve the material quality of the GaN layer. The GaN layer was then separated from the porous Si/Si substrate by immersing in an acidic solution. The surface of the freestanding patterned polycrystalline GaN substrate that was in contact with the porous Si/Si substrate consisted of cubic-like structures, as inherited from the porous Si/Si substrate. Although the cubic-like structures were almost uniformly distributed on the surface, they were formed in various heights due to irregular degree of symmetry of the porous Si/Si substrate. X-ray diffraction results suggested that β -Ga2 O3 inclusions are inside the freestanding patterned polycrystalline GaN substrate but not on its surface. This was supported by micro-photoluminecsence (PL) measurement, whereby only the GaN PL signals were observed. Furthermore, Raman spectroscopy revealed a small amount of compressive stress (0.23 GPa), suggesting that the substrate was almost relaxed.