Silicon anodic oxides grown in the oscillatory anodisation regime kinetics of growth, composition and electrical properties

Abstract The work presents the results of studying the anodic oxide growth at silicon in a special regime when the values of the anodic current or potential are oscillating in time. The oscillatory kinetics is ranging from intermittent and damped oscillations to very regular and long-lasting ones. The critical experimental factors allowing to observe well-defined oscillations are the composition of electrolyte, its temperature, anodic-current density (or voltage), electrolyte stirring, etc. Direct electron microscopy measurements show that the oscillations are due to the cyclic process of the formation of thin oxide films (10–100 nm, depending on the conditions of growth) and their pealing off from the surface of Si wafer. The surface works as a generator of these oxide films which according to the data of infrared measurements and secondary ion mass spectroscopy are composed of SiO 2 . Crystallographic orientation of Si wafers is an important factor in determining the shape of oscillations, presumably due to a specifics of the dissolution of different crystallographic planes of silicon. Analysis of the morphology of the samples and their kinetics of growth shows that the oscillatory anodisation kinetics is a self-organisation phenomenon emerging as a result of collective interactions in the electrolyte/Si system. DC and AC electrical conductivity of the formed oxide films are studied and shown to obey the hopping conductivity mechanisms. Transient effects in DC conductivity (charge trapping, structural relaxation, etc.) are studied using the frequency noise spectroscopy (FNS). It is shown that the FNS method allows to improve the reproducibility of the data due to its insensitivity towards macrostructural inhomogeneities of the oxide films.

[1]  Mark Schell,et al.  An experimental investigation of periodic and chaotic electrochemical oscillations in the anodic dissolution of copper in phosphoric acid , 1988 .

[2]  S. Timashev,et al.  Kinetics of porous silicon growth studied using flicker-noise spectroscopy , 2000 .

[3]  M. Sheintuch,et al.  Standing and propagating wave oscillations in the anodic dissolution of nickle , 1988, Nature.

[4]  H. Föll,et al.  A Model for Current‐Voltage Oscillations at the Silicon Electrode and Comparison with Experimental Results , 1999 .

[5]  F. Ozanam,et al.  Resonant and Nonresonant Behavior of the Anodic Dissolution of Silicon in Fluoride Media: An Impedance Study , 1992 .

[6]  A. V. Maximychev,et al.  Evolution of the Dynamic Dissipative Systems as a Temporal “Colour” Fractal , 1999 .

[7]  The Role of Stress and Percolation Effects on the Anodic Silicon Oxides Growth Mechanism , 2000 .

[8]  V. Parkhutik,et al.  The modelling of DC conductivity of thin disorder dielectrics , 1986 .

[9]  H. Pickering,et al.  Potential Distribution, Shape Evolution, and Modeling of Pit Growth for Ni in Sulfuric Acid , 1995 .

[10]  G. C. Jain,et al.  On the Mechanism of the Anodic Oxidation of Si at Constant Voltage , 1979 .

[11]  V. Parkhutik,et al.  Mechanism of large oscillations of anodic potential during anodization of silicon in H3PO4/HF solutions , 2000 .

[12]  M. Lübke,et al.  Electrolytic Growth and Dissolution of Oxide Layers on Silicon in Aqueous Solutions of Fluorides , 1988 .

[13]  V. Parkhutik.  Kinetics, composition and mechanism of anodic oxide growth on silicon in water-containing electrolytes , 1991 .

[14]  A. Vijh,et al.  Oxides and Oxide Films , 1974 .

[15]  Z. Nagy,et al.  X-Ray Reflectivity Study of Formation of Multilayer Porous Anodic Oxides of Silicon , 1999 .

[16]  Modeling the Complex Behavior of Microorganisms , 1999 .

[17]  S. Cattarin,et al.  In Situ Characterization of the p ‐ Si / NH 4 F Interface during Dissolution in the Current Oscillations Regime , 1998 .

[18]  J. L. Hudson,et al.  Electrochemical Reaction Dynamics - A Review , 1994 .

[19]  T. Dittrich,et al.  In Situ Monitoring of Electrochemical Processes at the (100) p‐Si/Aqueous NH 4 F Electrolyte Interface by Photoluminescence , 1997 .

[20]  H. Flietner,et al.  Optimization of Anodic Silicon Oxide Films for Low Temperature Passivation of Silicon Surfaces , 1993 .

[21]  V. Lehmann,et al.  On the Origin of Electrochemical Oscillations at Silicon Electrodes , 1996 .

[22]  A. Owen,et al.  Anodic Oxide Films for Device Fabrication in Silicon I . The Controlled Incorporation of Phosphorus into Anodic Oxide Films on Silicon , 1964 .