Real Time Observations of Dislocation-Mediated Plasticity in the Epitaxial Aluminum (110) / Silicon (001) Thin Film System

The mechanical behavior of metallic thin films on silicon plays a crucial role in the performance and reliability of microelectronic devices. A substantial body of research has focused on experimental methods for determining the mechanical properties of these systems as well as their response to thermomechanical stimuli. Of particular interest is a fundamental understanding of the how these films respond to the thermal expansion stresses that develop during typical microelectronic device fabrication steps.In this work, we present a series of real time in-situtransmission electron microscopy observations of the thermomechanical response of a model metal film on silicon system. Physical vapor deposition of approximately 50 nm of aluminum onto a clean Si substrate held at 280 °C results in the creation of an epitaxial bicrystalline film with two variants of Al (110) oriented grains. In order to observe a large, uniform area during in-situTEM thermal cycling, the Si substrate used was a SIMOX structure composed of 300 nm of Si (001) over 370 nm of buried SiO2).