Cr is often used in thin metallic film structures on oxide glasses since it
exhibits good adhesion. The most likely explanation of the basic adhesion
mechanism is the formation of a graded metal oxide layer at the interface.
In general, details of the interface properties are needed to get a complet
e understanding of phenomena such as adhesion. We report here observations
of interface structures using spatially resolved electron energy loss spect
rometry with a small probe (2 Angstrom) scanning transmission electron micr
oscope. Two interfaces, evaporated Cr/alkaline earth boroaluminosilicate gl
ass and sputtered Cr/barium boroaluminosilicate glass, are examined. As exp
ected from the classical adhesion theory, very thin partially oxidized inte
rmediate layers are seen in both samples. However, a 5 nm Cr diffusion laye
r is also found in the evaporated Cr/glass system (without heat treatment),
but it appears absent in the sputtered Cr glass system (with heat treatmen
t). This difference suggests that the mechanisms of the adhesion of Cr to o
xide glass are dependent on interface history. (C) 2000 American Institute
of Physics. [S0021-8979(00)05308-1].