AC Mode SMM Imaging of Soft Materials
Shijie Wu1Jing-Jiang Yu1Ferry Kienberger2
1. Agilent Technologies, Inc., Chandler, AZ, USA2. Agilent Technologies Austria GmbH, Measurement Research Lab, Gruberstrasse, Linz
摘要：Scanning microwave microscopy （SMM） is a recent development in SPM technique that combines an AFM with a vector network analyzer （VAN）. In the reflection mode （S11 measurement）, the measured complex reflection coefficient of the microwave from the contact point directly correlates to the impedance of the sample under test, and it is capable of measuring minute capacitance difference （10 -18 F） between materials and different regions on the sample surface, such as that between decanethiol and octadecanthiol SAM layers. SMM can also be used for doping structure characterization of semiconductor devices. Quantitative capacitance and dopant concentration measurement have been done by calibrating the measured capacitance, C, or dC/dV against known standard structures. However, SMM is a contact mode AFM technique. The AFM/microwave probe is in soft contact during the imaging scan, this prohibits the application of SMM to soft materials, thus hindering the application of SMM in the field of polymer and biology. It also shortens the life time of the probe due to wearing and deformation. In order to overcome these shortcomings intrinsic to contact imaging, we have explored the possibility of SMM measurements in oscillation Mode （ACSMM）. A mechanical actuator was used to oscillate the MW probe for AC mode imaging, at its fundamental resonance or higher order frequencies. Results on selected samples such as bacteria and polymer films will be reported in this presentation.
International Conference on Nanoscience & Technology,China 2013（ChinaNANO 2013）