Ion bombardment effects on nucleation of sputtered Mo nano-crystals in Mo/B4C/Si multilayers

Over recent years, the introduction of Mo/Si multilayers mirrors with different barrier layers for the interfaces has allowed increasing mirror reflectance, life and temperature stability. The effects of these very thin barrier layers on multilayer growth, such as interlayer formation and Mo crystallization, are not completely understood and deserve further study. This work shows, by using XRD and TEM analysis, that the crystallization thickness of the sputtered deposited Mo layers, when the boron carbide interlayer is present, increases from 2.0 nm to about 2.6 nm with respect to conventional Mo/Si multilayers. Furthermore some effects of ion energy bombardment on the nano-crystals formation and interlayer structure evolution have also been studied, showing an increase of preferential orientation for higher ion energies.

[1]  Oswald H. W. Siegmund,et al.  UV, X-Ray, and Gamma-Ray Space Instrumentation for Astronomy XVIII , 2007 .

[2]  Jiarui Liu,et al.  (α, α) Cross section on 11B for α-energies between 1.0 and 5.3 MeV , 1996 .

[3]  H. Takenaka,et al.  Thermal stability of Mo/C/Si/C multilayer soft X-ray mirrors , 1996 .

[4]  R. H. Stulen,et al.  Extreme ultraviolet lithography , 1998 .

[5]  Y. Kido,et al.  The atomic displacements on surface generated by low-energy projectile , 2000 .

[6]  V. Rigato,et al.  Structure and interface properties of Mo/B4C/Si multilayers deposited by rf-magnetron sputtering , 2004 .

[7]  M. Löhmann,et al.  Decay length of the pressure dependent deposition rate for magnetron sputtering , 1998 .

[8]  Mark T. Robinson,et al.  Computer studies of the reflection of light ions from solids , 1976 .

[9]  J. Lindhard,et al.  ENERGY DISSIPATION BY IONS IN THE kev REGION , 1961 .

[10]  Mark T. Robinson,et al.  Computer simulation of the self‐sputtering of uranium , 1983 .

[11]  Jiarui Liu,et al.  Cross-sections of 11B(p, α)8Be reaction for boron analysis , 2002 .

[12]  Piergiorgio Nicolosi,et al.  Effects of ion bombardment and gas incorporation on the properties of Mo/a-Si:H multilayers for EUV applications , 2003 .

[13]  R. Scholz,et al.  Mo/Si Multilayers with Different Barrier Layers for Applications as Extreme Ultraviolet Mirrors , 2002 .

[14]  Wolfgang Eckstein,et al.  Computer simulation of ion-solid interactions , 1991 .

[15]  R. Somekh.  The thermalization of energetic atoms during the sputtering process , 1984 .

[16]  M. Nastasi,et al.  The role of trapped Ar atoms in the mechanical properties of boron carbide films deposited by dc-magnetron sputtering , 2003 .

[17]  J. Biersack,et al.  Reflection of heavy ions , 1986 .

[18]  N. Carvalho,et al.  Characterization of mechanical properties of tungsten carbide/carbon multilayers: Cross-sectional electron microscopy and nanoindentation observations , 2001 .

[19]  Howard F. McMurdie,et al.  Phase diagrams for ceramists , 1964 .

[20]  P. Paufler,et al.  Thermal stability of Mo/Si multilayers with boron carbide interlayers , 2003 .

[21]  T. A. Carlson,et al.  X-ray and inner-shell processes , 1990 .

[22]  Saša Bajt,et al.  Molybdenum–ruthenium/beryllium multilayer coatings , 2000 .

[23]  C. J. Hailey,et al.  EUV, X-ray, and gamma-ray instrumentation for astronomy and atomic physics; Proceedings of the Meeting, San Diego, CA, Aug. 7-11, 1989 , 1989 .

[24]  S. Bajt,et al.  Investigation of the amorphous-to-crystalline transition in Mo/Si multilayers , 2001 .

[25]  Ye Feng,et al.  Cross sections for 165° backscattering of 2.0–9.0 MeV 4He from carbon , 1994 .