Thermal Analysis On The Damage Of HEMT Devices Induced By The High Power Microwave

High power microwave(HPM)is an important form of intense electromagnetic pulse.It can easily couple into electronic system through front door and back door path,and will induced electrical impulse in the electronic devices or lines,which brings a serious damage to the electronic system.And the rapid development of microwave pulse technology,it had been applied to military weapons by many countries.So the research of HPM effects to the electronic system will become increasingly important in the future.The high-electron mobility transistor(HEMT)is the core component of the low noise amplifier(LNA).And the HPM can easily couple into HEMT through the front door path,causing device damage or destroying electronic system.The direct cause of device damage is the high temperature signal injection.And the local temperature of the semiconductor device is too high,resulting in thermal damage.Therefore,it has great significance to study the thermal damage mechanism on the basis of high power microwave injection.In this paper,?-doped Al Ga As/In Ga As PHEMT device was used as the object of study,and the equivalent electrical pulse signal model of HPM was used as the simulation condition.The relationship between the thermal damage mechanism and the equivalent electrical pulse signal parameters is studied through numerical simulation.From the views of system thermal analysis and local hot spot analysis,discuss thermal tranformation in the device.And the basic principle of the semiconductor device and the mathematical physics are combined to obtain the mathematical model of the temperature in the device.The main contents of the paper are as follows:1.The software model of Ga As PHEMT device structure is established by Sentaurus TCAD software.Based on the physical phenomena in the actual device,the relevant numerical model is established and considered,and includes the carrier transport model,the mobility model and the carrier generation model.Consider the equivalent impulse signal model of HPM injection,which is used as the simulation condition of device gate injection.And the output characteristic curve and transfer characteristic curve of HEMT device software model are verified.The model foundation of HEMT device is established.2.Based on the previously established HEMT device simulation model,the thermal effect process of HEMT device is simulated by using step voltage signal injection.From the view of system thermal analysis,we built an equivalent thermal path model.Considering the relevant boundary conditions,the transient response of the device's temperature is studied.At the same time,considering the relationship between temperature and relaxation time when multiple pulses are injected,the process of temperature rise and fall and its thermal equation are obtained.In this paper,the thermal effect mechanism of pulse injection is discussed from the point of local thermal analysis.In the two cases,when the injection power is lower than the damage threshold,the device reaches the thermal steady state after several time.And when the injection power is large,the device temperature rises slowly at the beginning and gradually reaches a certain temperature,the suddenly increasing in temperature makes the device burned.And the mathematical model is established temperature in the device.The relationship between temperature and time in the hot spot of the device is obtained and compared with the simulation results.3.Based on the HPM equivalent electrical pulse signal model,the relationship between the hot spot temperature and the equivalent signal model parameters is discussed with the sinusoidal voltage pulse as the gate injection condition.The results show that the electric field,current and temperature appear peak at the bottom of the gate near the source side of the where is the highest hot spot in the device.In the discussion of the frequency effect,when the frequency is larger,the internal change of the electric field makes the carrier accumulation time reduced,the number of heat dissipation increases,more difficult to produce heat accumulation,the higher the damage power threshold.The carrier accumulation time decreases,the number of heat dissipation increases,the heat accumulation is more difficult,and the power threshold is higher due to the rapid change of the electric field.In the discussion of pulse width effect,the research shows that with the increase of pulse width,the time of heat accumulation increases,the power threshold is lower and the power threshold is higher.In the actual electromagnetic environment,HPM injection is not continuous.In the discussion of thermal effects of repetitive frequencies,studies have shown that pulse width and frequency are sensitive parameters of device damage.When the pulse width is constant,with the increase of the repetition frequency,the thermal dissipation time increases and the damage power threshold increases.When the frequency is constant,the increase of the pulse width leads to the increase of the heat accumulation time,the decrease of the heat dissipation time,burnout threshold is reduced.In this paper,the repetition of the pulse as a constant power input,we get the analytical formula of pulse width,frequency and burnout threshold.4.According to the results of previous numerical simulation and the mathematical model of Ga As PHEMT device structure,and the vertical electric field and horizontal electric field under the gate are calculated.The mathematical model of the electric field-current distribution is close to the simulation result.Because the main way of device's internal heat is Joule heat,thus we got the injection thermal power at the hot spot.In this paper,the peak thermal power is the heat injection at the hot spot.By solving the thermal equation,the curve of the hot spot temperature with the gate voltage is obtained.It get a good result compared with the simulation results,indicating the accuracy and feasibility of the analytical model.This is significant for the thermal effect analysis of HEMT devices under HPM injection.Based on the previous research,this paper makes a further theoretical exploration,and obtains the mathematical model of HPM injection and hot spot generation mechanism,which can predict the hotspot temperature trend of the device.It provides a theoretical basis for the damage effect and protection research of HEMT devices under HPM.