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Acoustic at microwave frequencies for thin film studies
Thin Solid Fibre, 84 ( 1981 ) 184
184
PREPARATION AND CHARACTERIZATION
A C O U S T I C S AT M I C R O W A V E F R E Q U E N C I E S F O R T H I N F I L M STUDIES* C. 1:. QI,JA'I'E
D~Tartment oJ Applied Physics, Stat?lord University, StanJbrd, ('A 94305 (U.S.A.)
In an imaging system based on high frequency acoustic waves, it has been shown that microscopic images can be recorded with a resolution that approaches that of the optical microscope. In this system, a focused beam of acoustic radiation is reflected from the substrate. It turns out that the reflectivity is sensitive to the elastic properties of the surface being studied. In a layered structure, as often encountered with thin film devices, the thickness as well as the adhesion of the layer to the substrate can be monitored, Variations in these two properties are displayed as changes in the image contrast. In an alternative method, the acoustic waves are generated through periodic heating of the surface. The heating can be produced either with a focused laser beam (photoacoustics) or with a focused electron beam. In either case, acoustic waves are generated and they can be used to monitor the amount of absorbed energy. Again, the imaging is on a microscopic scale and the variations in the thermal conduction of the layered surface are displayed in the image.
*Abstract of a paper presented at the International Conference on Metallurgical Coatings, San Francisco, CA, U.S.A., April 6. 10. 1981. 0040-6090.81 .'0000-0000S02.50
~. Elsevier Seq uoia:Printed in The Netherlands
184
PREPARATION AND CHARACTERIZATION
A C O U S T I C S AT M I C R O W A V E F R E Q U E N C I E S F O R T H I N F I L M STUDIES* C. 1:. QI,JA'I'E
D~Tartment oJ Applied Physics, Stat?lord University, StanJbrd, ('A 94305 (U.S.A.)
In an imaging system based on high frequency acoustic waves, it has been shown that microscopic images can be recorded with a resolution that approaches that of the optical microscope. In this system, a focused beam of acoustic radiation is reflected from the substrate. It turns out that the reflectivity is sensitive to the elastic properties of the surface being studied. In a layered structure, as often encountered with thin film devices, the thickness as well as the adhesion of the layer to the substrate can be monitored, Variations in these two properties are displayed as changes in the image contrast. In an alternative method, the acoustic waves are generated through periodic heating of the surface. The heating can be produced either with a focused laser beam (photoacoustics) or with a focused electron beam. In either case, acoustic waves are generated and they can be used to monitor the amount of absorbed energy. Again, the imaging is on a microscopic scale and the variations in the thermal conduction of the layered surface are displayed in the image.
*Abstract of a paper presented at the International Conference on Metallurgical Coatings, San Francisco, CA, U.S.A., April 6. 10. 1981. 0040-6090.81 .'0000-0000S02.50
~. Elsevier Seq uoia:Printed in The Netherlands