Electro-Thermal Characteristics of Junctionless Nanowire Gate-All-Around Transistors Using Compact Thermal Conductivity Model

Abstract

The electrothermal performance of a junctionless nanowire [JL-nanowire (NW)] gate-all-around (GAA) transistors under self-heating effect (SHE) is examined for sub-5 nm technology nodes. These devices are generally fabricated on silicon-on-insulator (SOI) wafers, in which the thin active device layer confines silicon thermal conductivity ( <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> and provokes SHE in the device. In this work, we proposed and upgraded the early reported compact thermal conductivity model (C-TCM) by considering the phosphorus doping effect for SHE analysis with any combination of doping, such as phosphorus/boron and arsenic/boron doping, which is validated with reported experimental data. The C-TCM is also compared with the existing Sentaurus TCAD Connelly thermal conductivity model (CN-TCM). The CN-TCM is only valid for undoped conditions at room temperature. This work shows that C-TCM can be used to simulate the realistic thermal behavior of the device with ambient temperature ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${T}_{A}{)}$ </tex-math></inline-formula> variation. With C-TCM, the nonuniform 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">${T}_{L}{)}$ </tex-math></inline-formula> and heat generation were observed along the channel length due to the non-uniformity <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> of the device. The influence of SHE on the device performance in terms of electrical characteristics and hot-carrier injection (HCI) is also observed along with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${T}_{A}$ </tex-math></inline-formula> variation. SHE rises the peak of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${T}_{L}{,}$ </tex-math></inline-formula> causing <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim $ </tex-math></inline-formula> 10% ON-current and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim $ </tex-math></inline-formula> 0.7% mobility degradation. The SHE implication on HCI is also examined, and it was found that gate leakage current ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{\text {G}}{)}$ </tex-math></inline-formula> is enhanced by a factor of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim $ </tex-math></inline-formula> 55, highlighting the importance of thermal study for next-generation high-performance devices that do not compromise reliability.