Nanoheteroepitaxial lateral overgrowth of GaN on nanoporous Si(111)

• Published in: Applied physics letters 2006-04, Vol.88 (14), p.141925-141925-3
• Main Authors: Zang, K. Y., Wang, Y. D., Chua, S. J., Wang, L. S., Tripathy, S., Thompson, C. V.
• Format: Article
• Language: English
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.2189114

Nanoheteroepitaxial (NHE) lateral overgrowth of GaN on nanoporous Si(111) substrates has been demonstrated. Nanopore arrays in Si(111) surfaces were fabricated using anodized aluminum oxide templates as etch masks, resulting in an average pore diameter and depth of about 60 and 160 - 180 nm , respectively. NHE growth of AlN and GaN was found to result in a significant reduction in the threading dislocation density ( < 10 8 cm − 2 ) compared to that on flat Si(111). Most dislocations that originate at the Si interface bent to lie in the GaN (0001) basal plane during lateral growth over the pore openings. E 2 phonon blueshifts in the Raman spectra indicate a significant relaxation of the tensile stress in the coalesced GaN films, due to three-dimensional stress relaxation mechanisms on porous substrates. Our results show that a single step lateral overgrowth of GaN on nanopatterned Si(111) substrates without a dielectric mask is a simple way to improve the crystalline quality of GaN layers for microelectronic applications.