重复频率下GaAs光电导开关的热积累研究  

Research on Thermal Accumulation of GaAs Photoconductive Semiconductor Switch at Repetition Rates

作　　者：高荣荣 徐鸣 罗伟 司鑫阳 刘骞[1] Gao Rongrong;Xu Ming;Luo Wei;Si Xinyang;Liu Qian(College of Science Xi’an University of Technology,Xi’an 710048,China)

机构地区：[1]西安理工大学理学院,西安710048

出　　处：《电工技术学报》2023年第15期4010-4018,共9页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金项目(52277164,51877177,52007152);陕西高校青年创新团队项目(超快光电器件与材料);中国博士后科学基金项目(2021M702639);陕西省科技计划重点项目(2021JZ-48);陕西省教育厅青年创新团队建设项目(21JP085,21JP088,22JP058)资助。

摘　　要：非线性模式下高密度丝状电流的热效应往往引发砷化镓光电导开关(GaAs PCSS)内部温度急剧上升,从而导致可靠性下降甚至热击穿,限制了器件的进一步应用。针对重复频率条件下光电导开关内部的热积累问题,基于理论分析构建二维模型,对高功率砷化镓光电导开关内部丝状电流温度分布进行模拟,获得了开关内部温度的时空变化规律。结果表明,由于材料自身的负微分迁移率(NDM)和导热系数等物理参数的影响,重复频率越高,热积累效应越明显。当重复频率为10 kHz时,温度最高升至1 262.73 K;在1 kHz重复频率触发下,丝状电流的直径较小(≤10μm)时,开关内部热积累效应不显著,当直径较大(>10μm)时,温度随着丝状电流直径的增加呈指数升高,温度最高可至871.43 K。该研究可为重复频率工作条件下大电流非线性GaAs PCSS的工作稳定性研究提供理论指导。Gallium arsenide photoconductive semiconductor switch(GaAs PCSS)is considered as one of the most promising ultrafast solid-state switching devices due to its excellent performance Such as switching speed,trigger jitter,output power and repetition rate.GaAs PCSS usually operates in two different modes:linear and nonlinear,but the thermal effect generated by the high carrier density filamentary current in the nonlinear mode can easily cause a sharp rise in the temperature inside the device,resulting in a decrease in device reliability and even thermal breakdown,which limits the further application of GaAs PCSS.Aiming at the thermal accumulation problem in GaAs PCSS at repetitive rates.Based on the theoretical analysis,a two-dimensional small-size model was constructed.Under the condition of power density of 5.04×10^(16) W/m^(3),the temperature distribution of the internal filamentary current of GaAs PCSS was simulated by finite element analysis software,and the temporal and spatial variation of the internal temperature of the PCSS was obtained.The simulation results show that,repetition rate and filamentary current diameter are the key physical parameters influencing the thermal accumulation in the PCSS,due to the influence of physical parameters such as negative differential mobility and thermal conductivity at high electric field.Firstly,considering the operation stability of nonlinear GaAs PCSS,the transient temperature distribution in the PCSS is investigated at 1 kHz repetition rate.The results show that the temperature increases with time and gradually diffuses deep into the material.At t=5 ms,the highest temperature of region near the anode x=0.543 mm,y=0.033 mm can reach 497.49 K.Secondly,the internal temperature variation of the PCSS is studied at different repetition rates when the filamentary current diameter d=50μm.The results show that the thermal effect is not obvious as the repetition rate is lower than 100 Hz.When the repetition rate is higher than 100 Hz,the increment of peak temperature increase

关 键 词：砷化镓光电导开关 热积累效应 重复频率 丝状电流 

分 类 号：O473[理学—半导体物理] TM89[理学—物理]