An XPS study of ion-induced compositional changes with group II and group IV compounds

Abstract Inert-gas ion bombardment and plasma etching are important processes in the fabrication and micromachining of semiconductor devices. Sequential ion etching and surface analysis is also widely employed as a means of device characterisation and investigation. In both applications, the incident ions produce topograhical and compositional changes in the surface region of the material. Changes in stoichiometry and oxidation state following ion-bombardment of a range of group II and group IV compounds have been studied by X-ray photoelectron spectroscopy (XPS). In every case, stoichiometry changes caused by ion-induced decomposition of the surface is observed, generally resulting in a preferential loss of the anionic species. Such behaviour is observed for the carbonates, sulphates and nitrates of group II and IV metals. The extent of cation reduction following ion-bombardment is found to be critically dependent on the composition and nature of the original surface. For example, Pb 2+ is stable to ion bombardment in all of the compounds studied, but is reduced to Pb 0 in the monoxide. The results are discussed in relation to the known thermodynamic properties of the compounds, and the experimental data are shown to correlate well with the free energies of formation in every case.

[1]  Roger Smith,et al.  The development of a general three-dimensional surface under ion bombardment , 1980 .

[2]  C. Bauer,et al.  Determination of the oxidation states of tin by Auger electron spectroscopy , 1981 .

[3]  A. E. Vries,et al.  The sputtering processes during 6 kev Xe ion beam bombardment of halides , 1978 .

[4]  J. Whitton,et al.  Change in stoichiometry of thin films of palladium chloride during ion beam analysis , 1978 .

[5]  R. Kelly,et al.  Preferential oxygen sputtering from Nb2O5 , 1976 .

[6]  N. Winograd,et al.  ESCA studies of metal-oxygen surfaces using argon and oxygen ion-bombardment , 1974 .

[7]  D. Chadwick,et al.  Oxidation of polycrystalline and (111) lead surfaces studied by electron spectroscopy , 1980 .

[8]  R. Holm,et al.  ESCA investigations of ion beam effects on surfaces , 1977 .

[9]  H. Werner.  Quantitative secondary ion mass spectrometry: A review , 1980 .

[10]  F. Viehböck,et al.  1.5 Effects in Auger electron spectroscopy due to the probing electrons and sputtering , 1977 .

[11]  R. L. Park,et al.  Flotation related ESCA studies on PbS surfaces , 1977 .

[12]  P. Sigmund.  Sputtering of single and multiple component materials , 1980 .

[13]  M. Klasson,et al.  Calibration of electron spectra , 1973 .

[14]  R. Holm,et al.  ESCA studies on changes in surface composition under ion bombardment , 1977 .

[15]  R. Kelly,et al.  The sputtering of oxides part i: a survey of the experimental results , 1973 .

[16]  D. J. Barber,et al.  The sputtering behaviour of calcite , 1978 .

[17]  D. Mccaughan,et al.  Low‐energy ion bombardment of silicon dioxide films on silicon. II. Inert ambient annealing of degradation in MOS devices , 1973 .

[18]  I. Sutherland,et al.  An XPS study of ion-induced dissociation on metal carbonate surfaces , 1981 .

[19]  P. Williams.  The sputtering process and sputtered ion emission , 1979 .

[20]  R. Kelly.  Thermal effects in sputtering , 1979 .

[21]  N. Winograd,et al.  X-ray photoelectron spectroscopic studies of PbO surfaces bombarded with He+, Ne+, Ar+, Xe+ and Kr+ , 1976 .

[22]  R. Kelly,et al.  Ion-impact chemistry in the system titanium-oxygen (studies on bombardment-enhanced conductivity—III) , 1974 .

[23]  N. Winograd,et al.  X-ray photoelectron spectroscopic studies of nickel-oxygen surfaces using oxygen and argon ion-bombardment , 1974 .

[24]  W. Spicer,et al.  Auger depth profiling of interfaces in MOS and MNOS structures , 1976 .

[25]  P. Holloway,et al.  Preferential sputtering of Ta2O5 by argon ions , 1979 .

[26]  T. Tsang,et al.  XPS studies of ion-bombardment damage of transition metal sulfides , 1980 .

[27]  A. Silfhout,et al.  The influence of argon ion bombardment on the electrical and optical properties of clean silicon surfaces , 1981 .

[28]  R. Kelly.  On the problem of whether mass or chemical bonding is more important to bombardment-induced compositional changes in alloys and oxides , 1980 .