The influence of AlxGa1-xN intermediate buffer layer on the characteristics of GaN/Si(1 1 1) epitaxy

• Published in: Journal of crystal growth Vol. 255; no. 3-4; pp. 220 - 226
• Main Authors: JANG, Seong-Hwan, LEE, Seong-Suk, LEE, Oh-Yeon, LEE, Cheul-Ro
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier 01.08.2003
• Subjects: Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Vapor phase epitaxy; growth from vapor phase; Buffer layer; Inorganic compounds; Gallium nitrides; Surfaces; VPE; A3. Metalorganic vapor phase epitaxy; Crystal growth from vapors; Experimental study; 85.15.Gh; Crystal perfection; Thin films; Solid solutions; Morphology; MOVPE method; Mismatch lattice; Aluminium nitrides; B1. AlxGa1-xN; Heterojunctions; Chemical composition; B1. GaN/Si; 68.55.-a A1. Composite buffer layer; III-V semiconductors; 81.05.Ea
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/s0022-0248(03)01251-x

The characteristics of GaN/Si(111) epitaxial layers grown by metalorganic vapor phase epitaxy (MOVPE) with AlxGa1-xN/AlN composite buffer layer(CBL) where x varies from 0.07 to 0.15 in AlxGa1-xN were investigated. The x values of AlxGa1-xN grown with various trimethyl-gallium (TMG) flow rates while feeding trimethyl-aluminum (TMA) flow constant were determined by triple crystal X-ray diffractometry (TCXRD). The surface images of GaN/Si(111) epitaxy observed by SEM show some cracks, which are due to thermal mismatch between GaN and Si. According to double crystal X-ray diffractometry (DCXRD) rocking curves of GaN(0002), the crystal quality of GaN/Si(111) grown on Al0.11Ga0.89N/AlN CBL exhibits the best result with FWHM of 886 arcsec. PL spectrum at RT of the GaN/Si(111) epitaxy grown on the CBL shows a sharp band edge emission peak at 365 nm with average FWHM of 45 meV, which is compared with the best result achieved so far for GaN/Si. Therefore, it can be concluded that the AlxGa1-xN/AlN CBL having suitable Al mole fraction of AlxGa1-xN layer plays an important role in improving the quality of GaN/Si(111) epitaxy by reducing the lattice and thermal mismatch between GaN and Si(111).