Phase stability and in situ growth stresses in Ti/Nb thin films

BCC stabilization and growth stress behavior in Ti/V multilayers

“…It was found in this system that the bcc transformed Ti layer revealed a significant amount of Nb interdiffusion which provided an additional chemical stabilizing effect on the transformation layer thickness when rationalized by the thermodynamic model described above [15,17]. The most recent investigation of Ti/Nb stability have involved the use of in situ stress measurements which noted a change in tensile-tocompressive stress at the bcc-to-hcp transition [17]. The use of such real-time measurements, particularly the stress evolution of a thin film, provides new insights into the relationship of how phase stability influences adatom mobility during film growth.…”

“…In respect to the system type studied in this paper, Ti has been reported to undergo a hcp to bcc transformations in Ti/Nb multilayers [15,17]. It was found in this system that the bcc transformed Ti layer revealed a significant amount of Nb interdiffusion which provided an additional chemical stabilizing effect on the transformation layer thickness when rationalized by the thermodynamic model described above [15,17]. The most recent investigation of Ti/Nb stability have involved the use of in situ stress measurements which noted a change in tensile-tocompressive stress at the bcc-to-hcp transition [17].…”

“…Thus, for sufficiently thin layers, the interfacial energy reduction can thermodynamically drive a change in phase and has been applied to various multilayer systems [17,18].…”

“…Both of these films are face centered cubic (fcc) and a transformation would not necessarily be expected. To the authors' knowledge, the use in situ stress evolution and its connection with phase stability has only been explicitly reported in Ti/Nb [17].…”

Residual stress measurement on TiN thin films by combing nanoindentation and average X-ray strain (AXS) method

“…Measurement of residual stress in thin films and coatings is crucial for understanding the evolution of growth stress [1][2][3][4][5][6][7][8] or thermal stress [5,9], and thereby improving the performance and reliability of microelectromechanical, electronic, magnetic and optical devices [4,[10][11][12][13][14]. For most mechanical applications, residual stress may affect elastic modulus [15], critical shear strength or adhesion [16,17], and fracture toughness [18], which usually leads to film delamination or spallation, especially for coatings on microelectromechanical systems (MEMS) and protective coatings [19][20][21].…”