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

The “pop-out” effect in ITO/Si and SnO2/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 SnO2/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 SnO2/Si structures (80–400 mN) within which the occurrence of the pop-out effect is most probable.