MULTI-PURPOSE METAL CANTILEVER TIP FOR SIMULTANEOUS AFM AND THERMAL IMAGING
Original Publication Date: 1993-Mar-01
Included in the Prior Art Database: 2002-Jan-28
The concept is essentially a micro-thermocouple (T-tip) for which micro-fabrication processes are used for manufacture. The T-tip can be used as a standard Atomic Force Microscope (AFM) tip for imaging sam- ple topography as well as a thermocouple to image local sample temperature. Figure 1 demonstrates the ability of the T-tip to simultaneously image topography and temperature. Figure la shows the standard AFM tech- nique in which the vertical deflections of a flexible canti- lever are monitored by a photo-detector as the sample is rastered in the x-y plane. Present tips are made from Silicon Nitride. Figure lb is a schematic of the proposed T-tip in which a layer of two dissimilar metals form a small junction which acts as a thermocouple junction. With this tip, the vertical deflections of the tip as it fol- lows the sample surface corrugations are monitored by the detector as before, but the local temperature at the surface can simultaneously be measured by monitoring the thermo-electric output between the two metals. Ther- mal contact is assured because the deflection feedback loop keeps the tip in classical contact with the surface Since the tip can be made very small, high resolution is possible in both topography and temperature. Present Silicon Nitride tips are capable of atomic resolution and the T-tip should have the same capability. Temperature resolution will be noise-limited which means a resolu- tion of approximately 10-4K is possible.