Isovalent Doping Reduces Channel Temperature Within Nanoscale Devices

Thermal bottleneck has become one of the main challenges for advanced semiconductor devices. Self-heating in transistors generates nanoscale hotspots with significant channel temperature rises that can deteriorate electrical performance and reliability. In this work, we propose a novel strategy that introduces simple isovalent channel doping to effectively reduce the high temperature rise within silicon-based FinFETs. By conducting a rigorous electrothermal simulation using the first-principles-based phonon Boltzmann transport equation (BTE), it is found that the temperature near hotspots in the channel significantly decreases after introducing isovalent doping, without inducing additional carriers to affect the device electrical performance. Germanium dopants with a concentration of less than 1% can lead to a decrease in the average channel temperature rise by more than 20%. It is revealed that this effect originates from suppressed phonon nonequilibrium by phonon–dopant scattering, resulting in more effective phonon transport near nanoscale hotspots. This mechanism has been demonstrated to be universal for other isovalent dopants, such as carbon, and is also more effective when the device is operating at low ambient temperatures. This work proposes a promising pathway for reducing the high channel temperature within FinFET-based electronics through device-level design, which is simple and compatible with current semiconductor process technologies. It can also be applied to new transistor architectures such as GAAFETs.