Enhancement of Thermal Characteristics and On-Current in GAA MOSFET by Utilizing Al2O3-Based Dual-κ Spacer Structure

By utilizing the dual-κspacer (DS) technique, a novel structure has been proposed to improve the thermal characteristics and ON-current (ION)in gate-all-around (GAA) MOSFETs. The proposed GAA MOSFET structure utilizes DS, which contains aluminum oxide (Al2O3) as an inner spacer so that the self-heating effect (SHE) could be improved from the high thermal conductivity of Al2O3. To verify the proposed device structure, 3-D technology computer-aided design (TCAD) simulation has been performed through Synopsys Sentaurus tool. As a result, when the DS structure and Al2O3 are utilized in GAA MOSFET, the maximum lattice temperature (Tₘₐₓ)is improved from 628 to 509 K, and the thermal resistance (Rₜₕ)is improved by 49%. According to this thermal improvement,IONand OFF-current (IOFF)are also simultaneously improved in the proposed GAA MOSFET. Furthermore, since Al2O3 has lower permittivity than HfO2, the gate capacitance (Cgate)could also be improved in the proposed GAA MOSFET. In essence, the proposed GAA MOSFET structure utilizes high thermal conductivity and low permittivity of Al2O3 with DS structure.