Mapping substrate/film adhesion with contact-resonance-frequency atomic force microscopy

We have used contact-resonance-frequency atomic force microscopy techniques to nondestructively image variations in adhesion at a buried interface. Images were acquired on a sample containing a 20 mn gold (An) blanket film on silicon (Si) with a 1 nm patterned interlayer of titanium (Ti). This design produced regions of very weak adhesion (Si/Au) and regions of strong adhesion (Si/Ti/Au). Values of the contact stiffness were 5% lower in the regions of weak adhesion. The observed behavior is consistent with theoretical predictions for layered systems with disbonds. Our results represent progress towards quantitative measurement of adhesion parameters on the nanoscale.