Silicon Nanoparticle Thermometers in the Transmission Electron Microscope

Since silicon is the primary constituent of most microelectronic devices, a technique with high spatial resolution capable of local temperature measurements in silicon would be extremely useful. Here we describe applying plasmon energy expansion thermometry (PEET) to perform non-contact temperature measurements on a silicon nanoparticle. In PEET, a transmission electron microscope (TEM) equipped with electron energy loss spectroscopy (EELS) is used to measure a sample’s bulk plasmon energy. The plasmon energy is related to valence electron density, which in turn is related to temperature via the sample’s coefficient of thermal expansion (CTE). Over a range from room temperature to 1250 °C, temperature measurements of a 100 nm silicon nanoparticle performed with PEET agree with those of the co-located, 300-micron wide, calibrated Joule heater/thermometer. The results are a promising first step towards mapping temperature in silicon nanowires and operating, highly-scaled transistors.