posted on 2021-12-27, 20:14authored byAmin Reihani, Yuxuan Luan, Shen Yan, Ju Won Lim, Edgar Meyhofer, Pramod Reddy
Quantitative
mapping of temperature fields with nanometric resolution
is critical in various areas of scientific research and emerging technology,
such as nanoelectronics, surface chemistry, plasmonic devices, and
quantum systems. A key challenge in achieving quantitative thermal
imaging with scanning thermal microscopy (SThM) is the lack of knowledge
of the tip–sample thermal resistance (RTS), which varies with local topography and is critical for
quantifying the sample temperature. Recent advances in SThM have enabled
simultaneous quantification of RTS and
topography in situations where the temperature field is modulated
enabling quantitative thermometry even when topographical features
cause significant variations in RTS. However,
such an approach is not applicable to situations where the temperature
modulation of the device is not readily possible. Here we show, using
custom-fabricated scanning thermal probes (STPs) with a sharp tip
(radius ∼25 nm) and an integrated heater/thermometer, that
one can quantitatively map unmodulated temperature fields, in a single
scan, with ∼7 nm spatial resolution and ∼50 mK temperature
resolution in a bandwidth of 1 Hz. This is accomplished by introducing
a modulated heat input to the STP and measuring the AC and DC responses
of the probe’s temperature which allow for simultaneous mapping
of the tip–sample thermal resistance and sample surface temperature.
The approach presented herecontact resistance resolved scanning
thermal microscopy (CR-SThM)can greatly facilitate temperature
mapping of a variety of microdevices under practical operating conditions.