基于声子水动力学方程分析全环绕栅极晶体管的瞬态热输运过程

Analysis of GAAFET’s transient heat transport process based on phonon hydrodynamic equations

相较于经典的傅里叶定律,声子水动力学模型在描述纳米尺度超快声子热输运中已经展现出显著优势.全环绕栅极晶体管(GAAFET)通过三维沟道设计极大优化了电学性能,但其纳米尺度特征也导致自热问题和局部过热的挑战.基于此,本文针对纳米尺度GAAFET器件内的声子热传输特性开展理论和数值模拟分析.首先,基于声子玻尔兹曼方程严格推导了声子水动力学模型和边界条件,建立了基于有限元的数值求解手段,针对新型的GAAFET器件,分析了表面粗糙度、沟道长度、沟道半径、栅极电介质、界面热阻等因素对其热传输特性的影响规律.研究结果表明,本文构建的连续介质框架下基于声子水动力学模型及温度跳跃条件的非傅里叶热分析方法能够精确预测GAAFET内部非傅里叶声子导热过程,并揭示声子阻尼散射和声子/界面散射的作用机制.这项工作为进一步优化GAAFET的热可靠性设计,提高其热稳定性和工作性能提供了重要的理论支持.

Compared to the classical Fourier’s law,the phonon hydrodynamic model has demonstrated significant advantages in describing ultrafast phonon heat transport at the nanoscale.The gate-all-around field-effect transistor(GAAFET)greatly optimizes its electrical performance through its three-dimensional channel design,but its nanoscale characteristics also lead to challenges such as self-heating and localized overheating.Therefore,it is of great significance to study the internal heat transport mechanism of GAAFET devices to obtain the thermal process and heat distribution characteristics.Based on this,this paper conducts theoretical and numerical simulation analyses on the phonon heat transfer characteristics within nanoscale GAAFET devices.Firstly,based on the phonon Boltzmann equation,the phonon hydrodynamic model and boundary conditions are rigorously derived,establishing a numerical solution method based on finite elements.For the novel GAAFET devices,the effects of factors such as surface roughness,channel length,channel radius,gate dielectric,and interface thermal resistance on their heat transfer characteristics are analyzed.The research results indicate that the larger the surface roughness,the smaller the channel length and the channel radius,the larger the interface thermal resistance leads to the higher hot spot peak temperature.The non-Fourier heat analysis method based on the phonon hydrodynamic model and temperature jump condition within the continuous medium framework constructed in this paper can accurately predict the non-Fourier phonon heat conduction process inside GAAFET and reveal the mechanisms of resistive scattering and phonon/interface scattering.This work provides important theoretical support for further optimizing the thermal reliability design of GAAFET,improving its thermal stability,and operational performance.