Nano-Probe Thermoreflectance Microscopy

Abstract

A nano-probe thermoreflectance microscope (NTM) can measure the thermal resistance of a GaN transistor or other device or sample with micron-scale spatial resolution. An NTM includes an atomic force microscopy (ATM) probe whose tip touches the sample. Either the ATM probe or the sample is heated, causing heat to flow between the sample and the ATM probe. This causes the temperature of the ATM probe to fluctuate. These temperature fluctuations cause the ATM probe's thermoreflectance to fluctuate in turn. An NTM measures the thermoreflectance fluctuations with a probe laser beam. If desired, a lock-in amplifier can modulate the heat flux between the ATM probe and sample, e.g., by modulating a stage that pushes the sample against the ATM probe, by modulating the amplitude of a pump laser beam focused on the ATM probe, or by modulating the drive current of the device under test, producing an amplitude modulation of the reflected probe laser beam at the same frequency.

Dependencies are inferred from the claim text.