基于电子-声子耦合的GaN HEMT产热和输运模拟研究  

Simulation of heat generation and transport of GaN HEMT based on electron-phonon coupling

作　　者：胡宝义 王照亮[1] 徐科[2] 唐大伟 HU BaoYi;WANG ZhaoLiang;XU Ke;TANG DaWei(School of New Energy,China University of Petroleum,Qingdao 266580,China;Suzhou Institute of Nano-Tech and Nano-Bionics(SINANO),Chinese Academy of Sciences,Suzhou 215123,China;School of Energy and Power Engineering,Dalian University of Technology,Dalian 116024,China)

机构地区：[1]中国石油大学(华东)新能源学院,青岛266580 [2]中国科学院苏州纳米技术与纳米仿生研究所,苏州215123 [3]大连理工大学能源与动力学院,大连116024

出　　处：《中国科学：技术科学》2024年第11期2107-2121,共15页Scientia Sinica(Technologica)

基　　金：国家自然科学基金项目(批准号:52276089和U22A20210)资助。

摘　　要：随着晶体管制程减小,器件的自热问题逐渐受到重视.为了精确描述晶体管器件内部电子-声子耦合产生局部热点的过程,本文以GaN HEMT为研究对象,提出了一种迭代求解的电子-声子耦合蒙特卡罗方法.该方法采用电子蒙特卡罗方法模拟电子输运过程,采用声子蒙特卡罗模拟声子输运过程,通过传递热源和温度场信息实现二者迭代求解.在电子蒙特卡罗方法中施加不同温度场,研究了热点产热的温度效应.发现温度上升后,峰值热点处发射声子减少,高频声子贡献增加,峰值热点处产热功率密度线性增大,每1 K温升导致产热功率密度上升1×10^(16)W/m^(3).迭代求解收敛后,产热功率密度和峰值温度有所上升,上升幅度受到初值影响.对热点作用下的声子输运进行分解,由于较大的比热容和群速度,低频声子的热流贡献更大.在热点影响下,高频声子热流贡献增加,最高可达35%,这种选择性激发造成了声子模式间的非平衡现象,阻碍了热输运过程.本文展现了电子-声子耦合过程中温度迭代的重要性,为晶体管自热效应模拟提供了参考.With decreasing transistor size, the self-heating effect of devices has received more and more attention. To accurately describe thelocal hot spots generated in transistor devices by electron-phonon coupling, this paper presents a coupled electron-phonon MonteCarlo method with an iterative solution by taking gallium nitride high-electron-mobility transistor as the research object. The electronMonte Carlo method is used to simulate the electron transportation process, and the phonon Monte Carlo method is used to simulatethe phonon transport process. Both these methods are solved iteratively by transferring the heat source and temperature fieldinformation. The temperature effect of hot spots is studied by applying different temperature fields in the electron Monte Carlomethod. After temperature rises, emission phonons at the peak hot spot decrease, the contribution of high-frequency phononsincreases, and power density at the peak hot spot increases linearly. Furthermore, power density increases by 1×10^(16)W/m^(3) for every1-K temperature rise. Once the iterative solution converges, heat generation power density and peak temperature increase, and theincreased amplitude is affected by the initial value. When phonon transport under a hot spot is decomposed, the heat flux contributionof low-frequency phonons increases due to their larger specific heat capacity and group velocity. Under the influence of hot spots, thecontribution of high-frequency phonon on heat flux increases by up to 35%. The selective excitation of hot spots causesnonequilibrium among phonon modes, which hinders the heat transport process to a certain extent. This work shows the importanceof temperature iteration in the electron-phonon coupling process and provides a reference for the self-heating effect simulation oftransistors.

关 键 词：GaN HEMT 电子-声子耦合 蒙特卡罗方法 温度效应 非平衡输运 

分 类 号：TN386[电子电信—物理电子学]