Reduction and Increase in Thermal Conductivity of Si Irradiated with Ga⁺ via Focused Ion Beam

Focused ion beam (FIB) technology has become a valuable tool for the microelectronics industry and for the fabrication and preparation of samples at the micro/nanoscale. Its effects on the thermal transport properties of Si, however, are not well understood nor do experimental data exist. This paper presents a carefully designed set of experiments for the determination of the thermal conductivity of Si samples irradiated by Ga⁺ FIB. Generally, the thermal conductivity decreases with increasing ion dose. For doses of >10¹⁶ (Ga⁺/cm²), a reversal of the trend was observed due to recrystallization of Si. This report provides insight on the thermal transport considerations relevant to engineering of Si nanostructures and interfaces fabricated or prepared by FIB.