Nondestructive Measurement of the Evolution of Layer-Specific Mechanical Properties in Sub-10 nm Bilayer Films.
We use short wavelength extreme ultraviolet light to independently measure the mechanical properties of disparate layers within a bilayer film for the first time, with single-monolayer sensitivity. We show that in Ni/Ta nanostructured systems, while their density ratio is not meaningfully changed from that expected in bulk, their elastic properties are significantly modified, where nickel softens while tantalum stiffens, relative to their bulk counterparts. In particular, the presence or absence of the Ta capping layer influences the mechanical properties of the Ni film. This nondestructive nanomechanical measurement technique represents the first approach to date able to distinguish the properties of composite materials well below 100 nm in thickness. This capability is critical for understanding and optimizing the strength, flexibility and reliability of materials in a host of nanostructured electronic, photovoltaic, and thermoelectric devices.
JILA and Department of Physics, University of Colorado , Boulder, Colorado 80309-0440, United States.
Kathleen M
KM
Hoogeboom-Pot
JILA and Department of Physics, University of Colorado , Boulder, Colorado 80309-0440, United States.
Emrah
E
Turgut
JILA and Department of Physics, University of Colorado , Boulder, Colorado 80309-0440, United States.
Jorge N
JN
Hernandez-Charpak
Electromagnetics Division, NIST , Boulder, Colorado 80305-3328, United States.
Justin M
JM
Shaw
JILA and Department of Physics, University of Colorado , Boulder, Colorado 80309-0440, United States.
Henry C
HC
Kapteyn
JILA and Department of Physics, University of Colorado , Boulder, Colorado 80309-0440, United States.
Margaret M
MM
Murnane
JILA and Department of Physics, University of Colorado , Boulder, Colorado 80309-0440, United States.
Damiano
D
Nardi
Ultrafast X-rays; monolayer sensitivity; nanomechanical properties; nanometrology; photoacoustics; ultrathin films