Enhancement of Thermal Characteristics and On-Current in GAA MOSFET by Utilizing Al<sub>2</sub>O<sub>3</sub>-Based Dual-κ Spacer Structure
Young Suh Song, Sangwan Kim, Jang Hyun Kim, Garam Kim, Jong‐Ho Lee, Woo Young Choi
Abstract
By utilizing the dual- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\kappa $ </tex-math></inline-formula> spacer (DS) technique, a novel structure has been proposed to improve the thermal characteristics and ON-current ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{ \mathrm{\scriptscriptstyle ON}}{)}$ </tex-math></inline-formula> 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 ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${T}_{\text {max}}{)}$ </tex-math></inline-formula> is improved from 628 to 509 K, and the thermal resistance ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R}_{\text {th}}{)}$ </tex-math></inline-formula> is improved by 49%. According to this thermal improvement, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{ \mathrm{\scriptscriptstyle ON}}$ </tex-math></inline-formula> and OFF-current ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{ \mathrm{\scriptscriptstyle OFF}}{)}$ </tex-math></inline-formula> are also simultaneously improved in the proposed GAA MOSFET. Furthermore, since Al2O3 has lower permittivity than HfO2, the gate capacitance ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${C}_{\text {gate}}{)}$ </tex-math></inline-formula> 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.