TY - JOUR

T1 - Fracture properties of thin film TiN at elevated temperatures

AU - Buchinger, J.

AU - Löfler, Lukas

AU - Ast, J.

AU - Wagner, A.

AU - Chen, Zhen

AU - Michler, J.

AU - Zhang, Zaoli

AU - Mayrhofer, Paul Heinz

AU - Holec, David

AU - Bartosik, Matthias

PY - 2020/6/13

Y1 - 2020/6/13

N2 - We provide an experimental and theoretical description of the high temperature fracture behaviour of TiN thin films. For this, we employ molecular dynamics and density functional theory, to show that the surface energies drop insignificantly between 0 and 1000 K. We utilise these results to predict a slight decrease of the fracture toughness over the aforementioned temperature range. For the experimental perspective, we use unbalanced DC reactive magnetron sputtering to synthesise a TiN film, on which we perform in situ high temperature microcantilever bending tests. Upon increasing the testing temperature from room temperature to 773 K our results present a slight, irreversible decrease of K IC, once the deposition temperature of the film (~653 K) is exceeded. Based on our theoretical groundwork, as well as complementary data produced by X-ray diffraction, nanoindentation, transmission electron microscopy, and wafer curvature measurements, we identify growth defect recovery as the main reason behind the decrease of K IC. We observe no change in the deformation and/or fracture mechanism of TiN across the experimentally investigated temperature range. Using an analytical model based on continuum mechanics, we estimate the influence of macro residual stresses on the temperature-dependent fracture toughness of TiN attached to a Si (100) wafer.

AB - We provide an experimental and theoretical description of the high temperature fracture behaviour of TiN thin films. For this, we employ molecular dynamics and density functional theory, to show that the surface energies drop insignificantly between 0 and 1000 K. We utilise these results to predict a slight decrease of the fracture toughness over the aforementioned temperature range. For the experimental perspective, we use unbalanced DC reactive magnetron sputtering to synthesise a TiN film, on which we perform in situ high temperature microcantilever bending tests. Upon increasing the testing temperature from room temperature to 773 K our results present a slight, irreversible decrease of K IC, once the deposition temperature of the film (~653 K) is exceeded. Based on our theoretical groundwork, as well as complementary data produced by X-ray diffraction, nanoindentation, transmission electron microscopy, and wafer curvature measurements, we identify growth defect recovery as the main reason behind the decrease of K IC. We observe no change in the deformation and/or fracture mechanism of TiN across the experimentally investigated temperature range. Using an analytical model based on continuum mechanics, we estimate the influence of macro residual stresses on the temperature-dependent fracture toughness of TiN attached to a Si (100) wafer.

UR - http://www.scopus.com/inward/record.url?scp=85086827680&partnerID=8YFLogxK

U2 - 10.1016/j.matdes.2020.108885

DO - 10.1016/j.matdes.2020.108885

M3 - Article

VL - 194.2020

SP - 1

EP - 10

JO - Materials & design

JF - Materials & design

SN - 0264-1275

IS - September

M1 - 108885

ER -