Aluminum oxide from trimethylaluminum and water by atomic layer deposition: The temperature dependence of residual stress, elastic modulus, hardness and adhesion

Abstract Use of atomic layer deposition (ALD) in microelectromechanical systems (MEMS) has increased as ALD enables conformal growth on 3-dimensional structures at relatively low temperatures. For MEMS device design and fabrication, the understanding of stress and mechanical properties such as elastic modulus, hardness and adhesion of thin film is crucial. In this work a comprehensive characterization of the stress, elastic modulus, hardness and adhesion of ALD aluminum oxide (Al2O3) films grown at 110–300 °C from trimethylaluminum and water is presented. Film stress was analyzed by wafer curvature measurements, elastic modulus by nanoindentation and surface-acoustic wave measurements, hardness by nanoindentation and adhesion by microscratch test and scanning nanowear. The films were also analyzed by ellipsometry, optical reflectometry, X-ray reflectivity and time-of-flight elastic recoil detection for refractive index, thickness, density and impurities. The ALD Al2O3 films were under tensile stress in the scale of hundreds of MPa. The magnitude of the stress decreased strongly with increasing ALD temperature. The stress was stable during storage in air. Elastic modulus and hardness of ALD Al2O3 saturated to a fairly constant value for growth at 150 to 300 °C, while ALD at 110 °C gave softer films with lower modulus. ALD Al2O3 films adhered strongly on cleaned silicon with SiOx termination.

[1]  Hannu Kattelus,et al.  Silicon full wafer bonding with atomic layer deposited titanium dioxide and aluminum oxide intermediate films , 2012 .

[2]  S. Timoshenko,et al.  Analysis of Bi-Metal Thermostats , 1925 .

[4]  Martti Blomberg,et al.  Monolithically integrated microspectrometer-on-chip based on tunable visible light MEMS FPI , 2012 .

[5]  S. George,et al.  Low-Temperature Al2O3 Atomic Layer Deposition , 2004 .

[6]  Frans Spaepen,et al.  Interfaces and stresses in thin films , 2000 .

[7]  Jinju Chen,et al.  Approaches to investigate delamination and interfacial toughness in coated systems: an overview , 2011 .

[8]  A. Krause,et al.  IR and NMR Study of the Chemisorption of Ammonia on Trimethylaluminum-Modified Silica , 2000 .

[9]  J. Wortman,et al.  Young's Modulus, Shear Modulus, and Poisson's Ratio in Silicon and Germanium , 1965 .

[10]  M. Ritala,et al.  In Situ Studies on Reaction Mechanisms in Atomic Layer Deposition , 2013 .

[11]  John B. Shoven,et al.  I , Edinburgh Medical and Surgical Journal.

[12]  Steven M. George,et al.  Al3O3 thin film growth on Si(100) using binary reaction sequence chemistry , 1997 .

[13]  T. Hecht,et al.  Mechanical stress in ALD-Al2O3 films , 2005 .

[14]  A. Krause,et al.  Successive reactions of gaseous trimethylaluminium and ammonia on porous alumina , 2001 .

[15]  R. Puurunen Preparation by Atomic Layer Deposition and Characterisation of Catalyst Supports Surfaced with Aluminium Nitride , 2002 .

[16]  G. Dingemans,et al.  Influence of the Deposition Temperature on the c-Si Surface Passivation by Al2O3 Films Synthesized by ALD and PECVD , 2010 .

[17]  Steven M. George,et al.  Surface Chemistry for Atomic Layer Growth , 1996 .

[18]  S. George Atomic layer deposition: an overview. , 2010, Chemical reviews.

[19]  Mikko Ritala,et al.  Effect of water dose on the atomic layer deposition rate of oxide thin films , 2000 .

[20]  Kai-Erik Elers,et al.  Film Uniformity in Atomic Layer Deposition , 2006 .

[21]  Michael Panzner,et al.  Non-destructive evaluation of diamond and diamond-like carbon films by laser induced surface acoustic waves , 1997 .

[22]  M. Ohring The Materials Science of Thin Films , 1991 .

[23]  I. Tittonen,et al.  Atomic layer deposited alumina (Al2O3) thin films on a high-Q mechanical silicon oscillator , 2007 .

[24]  James C. Greer,et al.  Simulating the atomic layer deposition of alumina from first principles , 2004 .

[25]  G. G. Stokes "J." , 1890, The New Yale Book of Quotations.

[26]  H. Kattelus,et al.  Electrically tunable surface micromachined FabryPerot interferometer for visible light , 2010 .

[27]  X. F. Wang,et al.  The influence of substrate on the adhesion behaviors of atomic layer deposited aluminum oxide films , 2011 .

[28]  K. L. Mittal,et al.  Adhesion Measurement of Thin Films , 1976 .

[29]  Wmm Erwin Kessels,et al.  Substrate-biasing during plasma-assisted atomic layer deposition to tailor metal-oxide thin film growth , 2013 .

[30]  Steven M. George,et al.  Surface chemistry of Al2O3 deposition using Al(CH3)3 and H2O in a binary reaction sequence , 1995 .

[31]  Miss A.O. Penney (b) , 1974, The New Yale Book of Quotations.

[32]  S. Gonczy,et al.  An ASTM Standard for Quantitative Scratch Adhesion Testing of Thin, Hard Ceramic Coatings , 2005 .

[33]  Helmut Baumgart,et al.  Nanoindentation Investigation of HfO2 and Al2O3 Films Grown by Atomic Layer Deposition , 2008 .

[34]  G. Pharr,et al.  An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiments , 1992 .

[35]  M. Ashby Overview No. 80: On the engineering properties of materials , 1989 .

[36]  J. M. Rafí,et al.  Deposition Temperature and Thermal Annealing Effects on the Electrical Characteristics of Atomic Layer Deposited Al2O3 Films on Silicon , 2011 .

[37]  William D. Nix,et al.  Mechanical properties of thin films , 1989 .

[38]  S. D. Elliott,et al.  Modelling the Deposition of High-k Dielectric Films by First Principles , 2004 .

[39]  Mikko Ritala,et al.  Crystallinity of inorganic films grown by atomic layer deposition: Overview and general trends , 2013 .

[40]  Victor M. Bright,et al.  The mechanical properties of atomic layer deposited alumina for use in micro- and nano-electromechanical systems , 2006 .

[41]  Milton Ohring,et al.  Materials science of thin films : deposition and structure , 2002 .

[42]  S. Bull Mechanical response of atomic layer deposition alumina coatings on stiff and compliant substrates , 2012 .

[43]  William D. Nix,et al.  Stresses and deformation processes in thin films on substrates , 1988 .

[44]  Steven M. George,et al.  Atomic-layer deposition of wear-resistant coatings for microelectromechanical devices , 2003 .

[45]  M. Ritala,et al.  In Situ Quartz Crystal Microbalance and Quadrupole Mass Spectrometry Studies of Atomic Layer Deposition of Aluminum Oxide from Trimethylaluminum and Water , 2001 .

[46]  R. Puurunen Correlation between the growth-per-cycle and the surface hydroxyl group concentration in the atomic layer deposition of aluminum oxide from trimethylaluminum and water , 2005 .

[47]  G. Stoney The Tension of Metallic Films Deposited by Electrolysis , 1909 .

[48]  Hiroyuki Fujita,et al.  Depth profiling of Al2O3 + TiO2 nanolaminates by means of a time-of-flight energy spectrometer , 2011 .

[49]  Wmm Erwin Kessels,et al.  Plasma and thermal ALD of Al2O3 in a commercial 200 mm ALD reactor , 2007 .

[50]  Mikko Ritala,et al.  Atomic layer deposition (ALD): from precursors to thin film structures , 2002 .

[51]  Y. Lee,et al.  Atomic layer deposited protective coatings for micro-electromechanical systems , 2003 .

[52]  W. Brantley Calculated elastic constants for stress problems associated with semiconductor devices , 1973 .

[53]  Hannu Kattelus,et al.  Implementing ALD Layers in MEMS Processing , 2007, ECS Transactions.

[54]  S. Senturia Microsystem Design , 2000 .

[55]  Victor M. Bright,et al.  Alternative dielectric films for rf MEMS capacitive switches deposited using atomic layer deposited Al2O3/ZnO alloys , 2007 .

[56]  Ultrathin oxide films by atomic layer deposition on graphene. , 2012, Nano letters.

[57]  J. M. Gray,et al.  Micromachined resonators of high Q-factor based on atomic layer deposited alumina , 2009 .

[58]  Zhanmiao Li,et al.  High-isolation lateral RF MEMS capacitive switch based on HfO2 dielectric for high frequency applications , 2012 .

[59]  Arthur S. Morris,et al.  Thermo-Mechanical Properties of Alumina Films Created Using the Atomic Layer Deposition Technique , 2010 .

[60]  Pekka Soininen,et al.  Perfectly Conformal TiN and Al2O3 Films Deposited by Atomic Layer Deposition , 1999 .

[61]  Veikko Lindroos,et al.  Handbook of Silicon Based MEMS Materials and Technologies , 2020 .

[62]  S. George,et al.  Quartz crystal microbalance studies of Al2O3 atomic layer deposition using trimethylaluminum and water at 125 degrees C. , 2010, The journal of physical chemistry. A.