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

By utilizing the dual- $\kappa $ spacer (DS) technique, a novel structure has been proposed to improve the thermal characteristics and ON-current ( ${I}_{ \mathrm{\scriptscriptstyle ON}}{)}$ 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 ( ${T}_{\text {max}}{)}$ is improved from 628 to 509 K, and the thermal resistance ( ${R}_{\text {th}}{)}$ is improved by 49%. According to this thermal improvement, ${I}_{ \mathrm{\scriptscriptstyle ON}}$ and OFF-current ( ${I}_{ \mathrm{\scriptscriptstyle OFF}}{)}$ are also simultaneously improved in the proposed GAA MOSFET. Furthermore, since Al2O3 has lower permittivity than HfO2, the gate capacitance ( ${C}_{\text {gate}}{)}$ 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.