Annealing of Al2O3 thin films prepared by atomic layer deposition

• Published in: Journal of physics. D, Applied physics Vol. 40; no. 12; pp. 3707 - 3713
• Main Authors: Zhang, L, Jiang, H C, Liu, C, Dong, J W, Chow, P
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 21.06.2007; Institute of Physics
• 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; Atomic force microscopy; Scanning electron microscopy; Frequency dependence; Crystallization; Roughness; XRD; Amorphous state; High temperature; Atomic layer epitaxial growth; Thin films; Rapid thermal annealing; Transmission electron microscopy; Capacitance; Aluminium oxides
• ISSN: 0022-3727; 1361-6463
• DOI: 10.1088/0022-3727/40/12/025

Amorphous Al2O3 thin films were deposited on a Si (1 1 1) substrate at 150 deg C in oxygen-rich conditions by atomic layer deposition. Rapid thermal annealing was performed at high temperatures, ranging from 1000 to 1200 deg C, to study the crystallization characteristics of the Al2O3 films. X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy, atomic force microscopy and frequency-dependent capacitance measurements were used to characterize the structural and electrical properties before and after the annealing. It was found that the best crystallization of the Al2O3 film was achieved after annealing at 1150 deg C, corresponding to a minimum of full width at half maximum (FWHM) of the Al2O3 (012) XRD peak and the maximum of surface roughness and the capacitances. This suggests that 1150 deg C is the optimal transition temperature from amorphous to crystalline and to get the best insulating property for Al2O3 thin film. The formation of the SiO2 interfacial layer after annealing has been observed by HRTEM for the annealed sample, accompanied by a decrease in the thickness of Al2O3 films.