RF Extraction of Self-Heating Effects in FinFETs

Multigate semiconductor devices are celebrated for improved electrostatic control and reduced short-channel effects. However, nonplanar architectures suffer from increases of access resistances and capacitances, as well as self-heating effects due to confinement and increased phonon boundary scattering. In silicon-on-insulator (SOI) technology, the self-heating effects are aggravated by the presence of a thick buried oxide with low thermal conductivity, which prevents effective heat removal from the device active region to the Si substrate. Due to the shrinking of device dimensions in the nanometer scale, the thermal time constant that characterizes the dynamic self-heating is significantly reduced, and radio frequency extraction techniques are needed. The dynamic self-heating effect is characterized in n-channel SOI FinFETs, and the dependence of thermal resistance on FinFET geometry is discussed. It is experimentally confirmed that the fin width and the number of parallel fins are the most important parameters for thermal management in FinFETs, whereas fin spacing plays a less significant role.