电工技术学报2024，Vol.39Issue(7)：2153-2160,8.DOI:10.19595/j.cnki.1000-6753.tces.230198
弱光触发下GaAs光电导开关的载流子输运和热失效机制
Carrier Transport and Thermal Failure Mechanism of GaAs Photoconductive Semiconductor Switch at Low Optical Excitation
摘要
Abstract
Gallium arsenide photoconductive semiconductor switch(GaAs PCSS)is one of the most promising solid-state switches with a simple structure,fast response time,low jitter,strong optical trigger isolation,and easy integration,which has a wide range of applications in terahertz technology,ultra-fast pulse sources,and high power microwave.GaAs PCSS has two operating modes:linear and high gain(HG).However,the conduction process of the HG GaAs PCSS is often accompanied by the high-density filamentary current under low optical energy(nJ-µJ),which generates a lot of Joule heat to damage device.In this paper,a two-dimensional(2D)electrothermal coupling model of GaAs PCSS is set up based on the self-heating effect,and the transient characteristics of the switch are investigated at the optical excitation of 1.5 µJ. Firstly,the output currents of HG GaAs PCSS under different bias electric fields are investigated.The results show that the corresponding output current waveforms have obvious trailing(lock-on),and the locking currents are almost the same at the optical excitation of 1.5 µJ as the bias electric field increases from 60 kV/cm to 78 kV/cm.In addition,the output current amplitude increases and the rise time decreases accordingly with the increase of the bias electric field. Secondly,the lattice temperatures of HG GaAs PCSS are investigated under different bias electric fields,considering the influence of the thermal field on the stability and physical process of the device.The results show that the rise of lattice temperature over time is divided into three stages combined with the current waveform,namely,the current rising stage,current descending stage and current lock-on stage.The rise rate of lattice temperature is determined by the bias electric field and the rise stage.The lattice temperature increases with the increase of the bias electric field,and the maximum lattice temperature can reach 821.92 K at the bias electric field of 78 kV/cm. Finally,the carrier transport process and thermal failure mechanism inside the switch are investigated by the distribution of the electric field,carrier concentration,impact ionization rate,and lattice temperature under single shot conditions.At t =10 ns,the high-field regions of the electric field,impact ionization rate,and lattice temperature are located near the electrodes.The values near the cathode are the maximum due to electron injection,which are 229 kV/cm,4.2×1025 cm-3·s-1,and 408.79 K,respectively.At t=50 ns,the filamentary current with a carrier concentration of 1017cm-3 is formed on the surface of GaAs PCSS through the anode and the cathode.The high-field regions of electric field,impact ionization rate,and lattice temperature are located near the anode,where the maximum values are 220 kV/cm,6.2×1022 cm-3·s-1,and 821.92 K,respectively.The relationship between the electric field,impact ionization rate,and lattice temperature is proven,which provides the possibility to predict the position of thermal breakdown. The relevant research provides the theoretical guidance for the study of carrier transport characteristic and damage mechanism of HG GaAs PCSS under the condition of high repetition rate.关键词
GaAs光电导开关/高倍增模式/丝状电流/输运机制Key words
GaAs photoconductive semiconductor switch/high-gain mode/filamentary current/transport mechanism分类
数理科学引用本文复制引用
司鑫阳,徐鸣,王文豪,常家豪,王铖杰..弱光触发下GaAs光电导开关的载流子输运和热失效机制[J].电工技术学报,2024,39(7):2153-2160,8.基金项目
国家自然科学基金项目(52277164,51877177)、陕西高校青年创新团队项目(超快光电器件与材料)、陕西省科技计划重点项目(2021JZ-48)和陕西省教育厅青年创新团队建设项目(21JP085,21JP088,22JP058)资助. （52277164,51877177）
