Pulsed microwave damage trend of bipolar transistor as a function of pulse parameters

In the present paper we conduct a theoretical study of the thermal accumulation effect of a typical bipolar transistor caused by high power pulsed microwave (HPM), and investigate the thermal accumulation effect as a function of pulse repetition frequency (PRF) and duty cycle. A study of the damage mechanism of the device is carried out from the variation analysis of the distribution of the electric field and the current density. The result shows that the accumulation temperature increases with PRF increasing and the threshold for the transistor is about 2 kHz. The response of the peak temperature induced by the injected single pulses indicates that the falling time is much longer than the rising time. Adopting the fitting method, the relationship between the peak temperature and the time during the rising edge and that between the peak temperature and the time during the falling edge are obtained. Moreover, the accumulation temperature decreases with duty cycle increasing for a certain mean power.     

Mechanical,elastic, anisotropy,and electronic properties of monoclinic phase of m-Si_xGe_(3-x)N_4

The structural,mechanical,elastic anisotropic,and electronic properties of the monoclinic phase of m-Si_3N_4,mSi_2GeN_4,m-SiGe_2N_4,and m-Ge_3N_4are systematically investigated in this work.The calculated results of lattice parameters,elastic constants and elastic moduli of m-Si_3N_4and m-Ge_3N_4are in good agreement with previous theoretical results.Using the Voigt–Reuss–Hill method,elastic properties such as bulk modulus B and shear modulus G are investigated.The calculated ratio of B/G and Poisson’s ratio v show that only m-SiGe_2N_4should belong to a ductile material in nature.In addition,m-SiGe_2N_4possesses the largest anisotropic shear modulus,Young’s modulus,Poisson’s ratio,and percentage of elastic anisotropies for bulk modulus ABand shear modulus AG,and universal anisotropic index AUamong m-Si_xGe_(3-x)N_4(x=0,1,2,3.)The results of electronic band gap reveal that m-Si_3N_4,m-Si_2GeN_4,m-SiGe_2N_4,and m-Ge_3N_4 are all direct and wide band gap semiconducting materials.     

Stability and performance analysis of a jump linear control system subject to digital upsets

This paper focuses on the methodology analysis for the stability and the corresponding tracking performance of a closed-loop digital jump linear control system with a stochastic switching signal. The method is applied to a flight control system. A distributed recoverable platform is implemented on the flight control system and subject to independent digital upsets. The upset processes are used to stimulate electromagnetic environments. Specifically, the paper presents the scenarios that the upset process is directly injected into the distributed flight control system, which is modeled by independent Markov upset processes and independent and identically distributed(IID) processes. A theoretical performance analysis and simulation modelling are both presented in detail for a more complete independent digital upset injection. The specific examples are proposed to verify the methodology of tracking performance analysis. The general analyses for different configurations are also proposed. Comparisons among different configurations are conducted to demonstrate the availability and the characteristics of the design.     

Hardening measures for bipolar transistors against microwave-induced damage

In the present paper we study the influences of the bias voltage and the external components on the damage progress of a bipolar transistor induced by high-power microwaves. The mechanism is presented by analyzing the variation in the internal distribution of the temperature in the device. The findings show that the device becomes less vulnerable to damage with an increase in bias voltage. Both the series diode at the base and the relatively low series resistance at the emitter, Re, can obviously prolong the burnout time of the device. However, Re will aid damage to the device when the value is sufficiently high due to the fact that the highest hot spot shifts from the base-emitter junction to the base region. Moreover, the series resistance at the base Rb will weaken the capability of the device to withstand microwave damage.     

双极晶体管微波损伤效应与机理

结合Si基n⁺-p-n-n⁺外延平面双极晶体管, 考虑了器件自热、高电场下的载流子迁移率退化和载流子雪崩产生效应, 建立了其在高功率微波(high power microwave, HPM)作用下的二维电热模型. 通过分析器件内部电场强度、电流密度和温度分布随信号作用时间的变化, 研究了频率为1 GHz的等效电压信号由基极和集电极注入时双极晶体管的损伤效应和机理. 结果表明集电极注入时器件升温发生在信号的负半周, 在正半周时器件峰值温度略有下降, 与集电极注入相比基极注入更容易使器件毁伤, 其易损部位是B-E结. 对初相分别为0和π的两个高幅值信号的损伤研究结果表明, 初相为π的信号更容易损伤器件, 而发射极串联电阻可以有效的提高器件的抗微波损伤能力.     

Microwave damage susceptibility trend of bipolar transistor as a function of frequency

We conduct a theoretical study of the damage susceptibility trend of a typical bipolar transistor induced by high-power microwave (HPM) as a function of frequency. The dependences of the burnout time and the damage power on the signal frequency are obtained. Studies of the internal damage process and the mechanism of the device are carried out from the variation analysis of the distribution of the electric field, current density, and temperature. The investigation shows that the burnout time linearly depends on the signal frequency. The current density and the electric field at the damage position decrease with increasing frequency. Meanwhile, the temperature elevation occurs in the area between the p-n junction and the n-n⁺ interface due to the increase of the electric field. Adopting the data analysis software, the relationship between the damage power and the frequency is obtained. Moreover, the thickness of the substrate has a significant effect on the burnout time.     

改进型异质栅对深亚微米栅长碳化硅MESFET特性影响

基于器件物理分析方法,结合高场迁移率、肖特基栅势垒降低、势垒隧穿等物理模型, 分析了改进型异质栅结构对深亚微米栅长碳化硅肖特基栅场效应晶体管沟道电势、 夹断电压以及栅下电场分布的影响.通过与传统栅结构器件特性的对比表明, 异质栅结构在碳化硅肖特基栅场效应晶体管的沟道电势中引入了多阶梯分布,加强了近源端电场; 另一方面,相比于双栅器件,改进型异质栅器件沟道最大电势的位置远离源端, 因此载流子在沟道中加速更快,在一定程度上屏蔽了漏压引起的电势变化,更好抑制了短沟道效应. 此外,研究了不同结构参数的异质栅对短沟道器件特性的影响,获得了优化的设计方案, 减小了器件的亚阈值倾斜因子.为发挥碳化硅器件在大功率应用中的优势,设计了非对称异质栅结构, 改善了栅电极边缘的电场分布,提高了小栅长器件的耐压.     

The pulsed microwave damage trend of a bipolar transistor as a function of pulse parameters

In the present paper we conduct a theoretical study of the thermal accumulation effect of a typical bipolar transistor caused by high power pulsed microwaves(HPMs),and investigate the thermal accumulation effect as a function of pulse repetition frequency(PRF) and duty cycle.A study of the damage mechanism of the device is carried out from the variation analysis of the distribution of the electric field and the current density.The result shows that the accumulation temperature increases with PRF increasing and the threshold for the transistor is about 2 kHz.The response of the peak temperature induced by the injected single pulses indicates that the falling time is much longer than the rising time.Adopting the fitting method,the relationship between the peak temperature and the time during the rising edge and that between the peak temperature and the time during the falling edge are obtained.Moreover,the accumulation temperature decreases with duty cycle increasing for a certain mean power.     

基极注入强电磁脉冲对双极晶体管的损伤效应和机理

建立了双极晶体管(BJT)在强电磁脉冲作用下的二维电热模型, 对处于有源放大区的BJT在基极注入强电磁脉冲时的瞬态响应进行了仿真. 结果表明, BJT烧毁点位置随注入脉冲幅度变化而变化, 低脉冲幅度下晶体管烧毁是由发射结反向雪崩击穿所致, 烧毁点位于发射结柱面区; 而在高脉冲幅度下, 由基区-外延层-衬底组成的p-n-n⁺ 二极管发生二次击穿导致靠近发射极一侧的基极边缘率先烧毁; BJT的烧毁时间随脉冲幅度升高而减小, 而损伤能量则随之呈现减小-增大-减小的变化趋势, 因而存在一个极小值和一个极大值. 仿真与实验结果的比较表明, 本文建立的晶体管模型不但能预测强电磁脉冲作用下BJT内部烧毁发生的位置, 而且能够得到损伤能量. 关键词： 双极晶体管 强电磁脉冲 烧毁点位置 损伤能量     

不同样式的高功率微波对双极晶体管的损伤效应和机理

结合Si基n⁺-p-n-n⁺ 外延平面双极晶体管, 通过分析器件内部的温度分布变化以及电流密度和烧毁时间随信号幅值的变化关系, 研究了其在三角波信号、正弦波信号和方波脉冲信号等三种样式的高功率微波信号作用下的损伤效应和机理. 研究表明, 三种高功率微波信号注入下器件的损伤部位都是发射结, 在频率和信号幅值相同的情况下方波脉冲信号更容易使器件损伤; 位移电流密度和烧毁时间随信号幅值的增大而增大, 而位移电流在总电流所占的比例随信号幅值的增大而减小; 相比于因信号变化率而引起的位移电流, 信号注入功率在高幅值信号注入损伤过程中占主要作用. 利用数据分析软件, 分别得到了三种信号作用下器件烧毁时间和信号频率的变化关系式. 结果表明, 器件烧毁时间随信号频率的增加而增加, 烧毁时间和频率都符合t= af^b的关系式. 关键词： 双极晶体管 高功率微波 损伤机理 信号样式