Investigation of Electro-Thermal Performance for TreeFET from the Perspective of Structure Parameters

In this work, the electro-thermal properties of TreeFET, which combines vertically stacked nanosheet (NS) and fin-shaped interbridge (IB) channels, are investigated in terms of interbridge width (WIB), nanosheet space (SNS) and nanosheet width (WNS) by TCAD simulation. Electrical characteristics such as electron density distributions, on/off-state current (ION, IOFF), subthreshold swing (SS) and self-heating effects (SHE) such as lattice temperature and thermal resistance (Rth) are systematically studied to optimize the performance of TreeFET. The result shows that a smaller WIB mitigates the short-channel effects and increases the electron concentration in NS channels but increases thermal resistance. A larger SNS increases the on-state current while compensating for the gate drive loss and mitigating the thermal coupling effect between NS channels but results in longer conduction paths of carriers and heat, which hinders further improvements. Moreover, a suitable WNS is required to lessen the decline of gate controllability induced by IB channels. Hence, suitable geometry parameters should be selected to achieve a compromise between thermal and electrical performance.