Thermal cycling fatigue in aluminum-alloy thin films on silicon substrate

Thermal cycling was performed in Al-1mo%Si thin films deposited on Si wafers. After a given number of cycling between room temperature and 723 K, residual stress was measured at room temperure. Residual stress was found to increase with increasing the cycling number up to the 4th cycle, followed by further a continuous decrease by further cycling. The intial increase was found to be related to the increase of lattice dislcocations and their tangling. The following decrease was caused by crack formation along grain boundaties or by film delamination in some cases.