Temperature Characteristic Research Of AlGaN/GaN HEMT Device

Semiconductor devices are nowhere to be seen in everyday life,such as mobile phones,computers,and even cars,and such a series of electronic equipment,and plays an important role in the national life.Al GaN/GaN HEMT devices are based on gallium nitride,so they have a unique condition at higher frequencies,higher temperatures,and higher power environments as a typical representative of third-generation semiconductor devices.However,the HEMT devices which work in the long-term work at high temperatures will appear some characteristics of degradation,such as saturation drain current decreases,power consumption,etc.,so we must analyze its temperature characteristics.On this purpose,We especially research for Al GaN/GaN HEMT device temperature characteristics of in-depth.The specific content is as follows:Firstly,the temperature characteristics of Al GaN/GaN HEMT devices were simulated.Based on Silvaco software,the device simulation of temperature 300 K ~ 500 K is carried out.The simulation results show that the maximum saturation output current density of the device decreasing with the temperature,and the peak voltage transconductance is decreasing.The results are mainly due to the decrease of the two-dimensional electron gas mobility in the Al GaN/GaN HEMT device channel at high temperature,which leads to the degradation of the device.Based on this,we study the effect of temperature on the new type of plate-type structure.We find that the maximum saturation output current to the field-type structure device is much larger than the conventional device,and the threshold voltage of the field plate structure device is smaller relative to the conventional device.But,We have obtained the same conclusion as the conventional structure device.Secondly,Experimental study on the temperature characteristics of Al GaN/GaN HEMT devices was carried out.In view of the typical requirements of high temperature application of HEMT devices we set a series of researching conditions like temperature experiment,high temperature thermal storage experiment,annealing experiment.The degradation behavior of typical Al GaN/GaN HEMT devices under different temperature conditions is studied systematically,including the saturation drain current,threshold voltage,peak transconductance,etc..The experimental results show that with the increaseof temperature,the saturation leakage current and peak transconductance of the device are decreasing and the threshold voltage is drifting positive.Thirdly,Experimental study on the temperature characteristics of ohmic contact of HEMT devices was carried out.Aiming at the key process of ohmic contact,a new ohmic contact parameter extraction structure is designed,and the ohmic contact block resistance is measured by TLM method and "end" resistance method respectively.On this basis,combined with the temperature experiment,the influence of temperature on the resistance of the ohmic contact block is obtained.The experimental results show that the resistance of the ohmic contact increases as the temperature increases.The reason for this is that the conductivity of the ohmic electrode region decreasing as the temperature increasing.Due to time constraints,there are still some problems in this paper to be further studied including annealing temperature which can be strengthened research in follow-up studies.At the same time,in the temperature experiment,we can also broaden the range of temperature.The work of this paper provides important and valuable support for the development of advanced Al GaN/GaN HEMTs in our country.