Nanostructured Silver Films with a Low Coefficient of Thermal Expansion as a Promising Material for Nanoelectronics

The results of a study of the thermal expansion of thin silver films obtained by thermal vacuum evaporation are presented. It is shown that, after single heating, the films consist of two types of crystallites. The nanosized fraction, for which the main area of the film is accounted, is represented by crystallites with a size of 50-60 nm. In addition to them, separate grains of hundreds of nanometers in size are observed in the samples, many of which are formed during the condensation process. The coefficient of linear thermal expansion of nanocrystalline films which is only 7 x 10(-6) K-1 is determined by electron diffraction using the method of measurement standard. This is significantly lower than the value which is typical for bulk samples. The decrease in the coefficient of thermal expansion is explained by the nanocrystalline nature of the films. The closeness of the obtained value to the coefficient of thermal expansion of silicon and germanium allows us to consider the use of nanocrystalline silver films as an effective way to improve the reliability and efficiency of modern and prospective microelectronics.