Dielectric properties of DC reactive magnetron sputtered Al2O3 thin films

Alumina (Al2O3) thin films were sputter deposited over well-cleaned glass and Si substrates by DC reactive magnetron sputtering under various oxygen gas pressures and sputtering powers. The composition of the films was analyzed by X-ray photoelectron spectroscopy and an optimal O/Al atomic ratio of 1.59 was obtained at a reactive gas pressure of 0.03 Pa and sputtering power of 70 W. X-ray diffraction results revealed that the films were amorphous until 550 degrees C. The surface morphology of the films was studied using scanning electron microscopy and the as-deposited films were found to be smooth. The topography of the as-deposited and annealed films was analyzed by atomic force microscopy and a progressive increase in the rms roughness of the films from 3.2 nm to 4.53 nm was also observed with increase in the annealing temperature. Al-Al2O3-Al thin film capacitors were then fabricated on glass substrates to study the effect of temperature and frequency on the dielectric property of the films. Temperature coefficient of capacitance. AC conductivity and activation energy were determined and the results are discussed. (C) 2011 Elsevier B.V. All rights reserved.

[1]  M. Radhakrishna,et al.  Characterization of Al2O3 thin films prepared by spray pyrolysis method for humidity sensor , 2007 .

[2]  I. Safi,et al.  Recent aspects concerning DC reactive magnetron sputtering of thin films: a review , 2000 .

[3]  S. Maniv,et al.  Oxidation of an aluminum magnetron sputtering target in Ar/O2 mixtures , 1980 .

[4]  D. Campbell,et al.  Selection of thin film capacitor dielectrics , 1968 .

[5]  C. Deshpandey,et al.  Preparation and properties of Al2O3 films by d.c. and r.f. magnetron sputtering , 1982 .

[6]  H. Morgner,et al.  Structure and properties of Al2O3 layers deposited by plasma activated electron beam evaporation , 2002 .

[7]  F. Argall,et al.  Dielectric properties of thin films of aluminium oxide and silicon oxide , 1968 .

[8]  D. K. Aswal,et al.  MORPHOLOGY AND RESISTIVITY OF AL THIN FILMS GROWN ON SI (1 1 1) BY MOLECULAR BEAM EPITAXY , 2005 .

[9]  M. Abkowitz,et al.  Electrical Properties of Amorphous Se, As 2 Se 3 , and As 2 S 3 , 1971 .

[10]  H. Birey,et al.  Dielectric properties of aluminum oxide films , 1978 .

[11]  A. Jonscher.  Alternating current diagnostics of poorly conducting thin films , 1976 .

[12]  D. W. Sheel,et al.  Atmospheric Pressure Glow Discharge CVD of Al2O3 Thin Films , 2006 .

[13]  P. Katiyar,et al.  Electrical properties of amorphous aluminum oxide thin films , 2005 .

[14]  Built-in interface in high-κ gate stacks , 2003 .

[15]  W. H. Gitzen.  Alumina as a ceramic material , 1970 .

[16]  M. Afifi,et al.  Ac conductivity and dielectric properties of amorphous In2Se3 films , 2001 .

[17]  T. Serikawa,et al.  Reactive sputtering characteristics of silicon in an ArN2 mixture , 1986 .

[18]  R. French.  Electronic Band Structure of {Al2O3}, with Comparison to Alon and {AIN} , 1990 .

[19]  R. Saravanakumar,et al.  AC and dielectric properties of vacuum evaporated InTe bilayer thin films , 2010 .

[20]  C. Merckling,et al.  Pseudomorphic molecular beam epitaxy growth of γ-Al2O3(001) on Si(001) and evidence for spontaneous lattice reorientation during epitaxy , 2006 .

[21]  E. Suh,et al.  Dielectric and transport properties of magnetron sputtered titanium dioxide thin films , 2005 .

[22]  P. Juliet,et al.  Surface defects and arc generation in reactive magnetron sputtering of aluminium oxide thin films , 1999 .

[23]  S. Shah,et al.  Reactive sputter deposition of alumina thin films using a hollow cathode sputtering source , 2002 .

[24]  D. Sastikumar,et al.  Structural and optical properties of γ-alumina thin films prepared by pulsed laser deposition , 2010 .

[25]  A. Jonscher,et al.  Electronic properties of amorphous dielectric films , 1967 .

[26]  E. Wallin,et al.  Phase control of Al2O3 thin films grown at low temperatures , 2006 .

[27]  G. Baud,et al.  Study and optimization of alumina and germanium dioxide and their multilayer capacitor properties , 2000 .

[28]  Sören Berg,et al.  A physical model for eliminating instabilities in reactive sputtering , 1988 .

[29]  R. D. Gould,et al.  A.c. electrical properties of thermally evaporated thin films of copper phthalocyanine , 1993 .

[30]  P. Zeman,et al.  Thermal stability of alumina thin films containing γ-Al2O3 phase prepared by reactive magnetron sputtering , 2010 .