Displaying items by tag: Raman

Monday, 04 May 2015 23:14

Silicon

 

Silicon

SECM with Raman Scattering in situ

Nanonics systems provide unique liquid-based capabilities in scanning electrochemical microscopy (SECM) that now for the first time can be combined with other SPM methods such as AFM-Raman for chemical imaging together with the topographic and electrochemical current imaging.  The Nanonics SECM capability incorporates Nanonics innovations in probe design, tip-sample feedback, and liquid cell design to enable new and revolutionary capabilities for the most advanced experiments.

Nanonics manufactures custom SECM probes with a continuous nanowire of platinum embedded in glass.  A side view is shown below on the left left while a top view is shown below on the right clearly showing the platinum wire and glass.  In the top-view, the white spot in the middle is the wire while the black ring around it is the glass.

Click the images below to download a detailed PDF description:

 

These custom probes provide simultaneous normal force sensing with full SECM functionality.  

Furthermore Nanonics provides a custom-designed liquid cell and environmental chamber to use in such measurements. 

For SECM measurements, the Raman setup through the laser, spectrometer, and CCD camera are placed above the probe with the optically friendly scanner and probe. Fluid measurements are doing using the critically important water immersion objective.  The placement of the SPM controller for AFM measurement and Potentistat for the SECM current measurements are shown on the right of the schematic.

SECM-Raman Application:  Simultaneous SECM current and Raman imaging of copper during real-time etching

A silicon wafer with a thin layer of copper was used as the substrate for this electrochemical etching experiment.   The SPM probe etched a small, ~4 um hole within the copper layer exposing the silicon substrate.   Images of the substrate before (left)  and after (right)  the etching can be seen below with the etched point showing up as a dark spot in the right image.

 

The etching was monitored in real time with in situ Raman scattering where the Raman signature of silicon at 523 cm-1 was used to track the appearance of the silicon and thus progress of the etching process.  A sample spectrum revealing the Si peak in the Raman spectrum is shown here: 

Published in Application Notes