“Pop-out” effect in ITO/Si and SnO2/Si structures

The “pop-out” effect in ITO/Si and SnO 2 /Si structures and in silicon used as a substrate is studied. The following pattern is observed for all the materials under study (the ITO/Si and SnO 2 /Si structures and the Si substrate): the occurrence of the pop-out effect heavily depends on the maximum applied load ( P max ) and less significantly depends on the unloading rate. The internal energy accumulation in the volume beneath the indent should be regarded as a cause of the pop-out effect. In addition, defect structures characteristic of each P max are formed in the hydrostatic pressure region beneath the indent. These defect structures determine the relaxation pattern during unloading and provide favorable conditions for the occurrence of the pop-out effect. It is shown that there is a certain load range for the Si substrate (40–300 mN) and for the ITO/Si and SnO 2 /Si structures (80–400 mN) within which the occurrence of the pop-out effect is most probable.