Comparative study of n-type AlGaN grown on sapphire by using a superlattice layer and a low-temperature AlN interlayer

• Published in: Journal of crystal growth Vol. 299; no. 1; pp. 59 - 62
• Main Authors: Xi, Y.A., Chen, K.X., Mont, F., Kim, J.K., Schubert, E.F., Liu, W., Li, X., Smart, J.A.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.02.2007; Elsevier
• Subjects: A3. Metalorganic vapor phase epitaxy; B1. AlGaN; B1. Nitride; B3. Light emitting diode; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Iii-v semiconductors; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Photoluminescence; Physics; 78.55.Cr; B1. Nitride; B3. Light emitting diode; B1. AlGaN; 73.61.Ey; A3. Metalorganic vapor phase epitaxy; 81.15.Gh; 81.05.Ea; Interlayers; Atomic force microscopy; A3. Metalorganic vapor phase epitaxy; B1. AIGaN; B1. Nitride; B3. Light emitting diode; Gallium nitrides; Secondary ion mass spectrometry; Hall effect; XRD; Silicon additions; High-resolution methods; Nitrides; Secondary ion mass spectra; MOVPE method; Superlattices; Aluminium nitrides; 81.15.Gh; 81.05.Ea; 78.55.Cr; 73.61.Ey; SIMS; Comparative study; Low temperature; III-V semiconductors
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2006.10.253

Si-doped Al 0.3Ga 0.7N grown on (0 0 0 1)-oriented sapphire is optimized by using a superlattice (SL) layer. Atomic force microscopy (AFM), high-resolution X-ray diffraction (HRXRD), secondary ion mass spectrometry (SIMS), and Hall effect measurements show that n-type Al 0.3Ga 0.7N grown on a SL layer gives high-quality crystalline and electrical properties. A 1.8-μm-thick crack-free n-type Al 0.3Ga 0.7N layer is demonstrated with a doping concentration of 3×10 18 cm –3, an excellent mobility of 80 cm 2/(V s), and an RMS roughness of 0.40 nm. Using the SL layer also results in the absence of hexagonal hillocks on the AlGaN surface, which are indicative of a high defect density. The study of an identical n-type Al 0.3Ga 0.7N layer grown on a low-temperature AlN interlayer shows a lower carrier concentration, mobility, and crystalline quality.