PFM Performances Analysis of PZT Piezoelectric Nano Cantilevers Fabricated on Si Wafer

We present in this work and for the first time a high level of integration of piezoelectric nano-cantilevers on a silicon substrate (4 inches in diameter). We use lead titanate – zirconate material as piezoelectric material mainly because of its excellent piezoelectric activity at macro scale. However, its integration within a silicon technological process is limited by the difficulty of structuring this material with sub micrometer resolution at the wafer scale. At the nano-scale many questions still remain unanswered. For example: what becomes of the piezoelectric activity? What are the limitations of the integration level process? What are the best electrodes (bottom and top) for piezoelectric film actuation? In this study we have tried to answer some of these fundamental questions. To this end, we have developed a specific patterning method based on deep UV lithography to fabricate nano cantilevers with a high density of integration. The main objective is to obtain sub-micron features by lifting off a 70-nm thick PZT layer while preserving the material’s piezoelectric properties. We show that for the actuation of a very thin film the choice of the bottom and top electrodes has a strong influence. To analyse the piezoelectric activity at nano scale we use the Piezo Force Microscopy, this measurement approach is a good characterization tool for piezoelectric nano devices