Study On The Thermoelectric Reliability Of AlGaN/GaN HEMTs And The Influence Of Annealing On Hydrogen Effect

AlGaN/GaN HEMTs are high-performance,high-speed,and high-power semiconductor devices widely used in fields such as power electronics,radar,communication,and satellite communication.However,in practical applications,AlGaN/GaN HEMTs also face thermoelectric reliability issues,which seriously affect device performance and reliability,and restrict the application of AlGaN/GaN HEMTs.Conducting research on the thermoelectric reliability of AlGaN/GaN HEMTs can help improve their stability and reliability in thermoelectric environments.In addition,hydrogen is also one of the factors affecting the reliability of AlGaN/GaN HEMTs.Finding a method to reduce the impact of hydrogen on their electrical performance can improve the reliability and stability of devices and promote their development in practical applications.Based on this,this study focuses on the reliability issues of AlGaN/GaN HEMTs in three aspects:temperature variation characteristics,step bias electrical stress degradation,and high temperature annealing of hydrogen effect AlGaN/GaN HEMTs.By comparing the DC and AC characteristics of AlGaN/GaN HEMTs before and after different stress environments,the degradation mechanism of the devices was analyzed,and the degradation model was validated using low-frequency noise analysis technology.The specific research content is as follows:1.Based on high-temperature reliability testing,DC characteristics,and AC characteristics analysis methods,the variable temperature characteristics of AlGaN/GaN HEMTs were studied.It was found that as the temperature increased,the threshold voltage of the device shifted slightly forward,the peak transconductance decreased slightly,the output leakage current decreased,the current collapse rate decreased,and the gate delay characteristics did not show significant changes.Through analysis,it is considered that the high-temperature degradation of the device is caused by the reduction of electron mobility and two-dimensional electron gas density.We also conducted thermoelectric coupling stress experiments with reverse bias at high temperatures and found that the electrical performance of the device deteriorates more severely than single high-temperature stress and reverse bias stress.There may be a high-temperature induced reverse bias degradation mechanism,which exacerbates the degradation.2.Steped bias stress experiments were conducted on AlGaN/GaN HEMTs.The experimental results show that under stepped bias stress,the saturation drain current of AlGaN/GaN HEMTs decreased and the threshold voltage shifted to the positive direction.Through analyzed,the degradation mechanism of steped bias stress was determined,which is the virtual gate effect.In addition,by analyzd the gate leakage current,it was found that step bias stress can reduce the gate leakage current of the device and optimize the Schottky characteristics of the device.3.For the first time,high-temperature annealing research was conducted on the hydrogen effect of AlGaN/GaN HEMTs,and it was found that high-temperature annealing reduced the impact of hydrogen on the electrical performance of the device.Extracting the defect density of hydrogen effect AlGaN/GaN HEMTs before and after high-temperature annealing using the relationship model between low-frequency noise characteristics of devices and defects,with values of 9.27×10²¹e V^-1·cm^-3 and1.43×10²¹ e V^-1·cm^-3,reveals the mechanism of high-temperature induced trap dehydrogenation.The degradation mechanism of AlGaN/GaN HEMTs under high temperature,high field,and hydrogen stress was revealed through the study of their thermoelectric reliability and the effect of annealing on hydrogen treatment.It is proposed that high-temperature annealing can reduce the influence of hydrogen on AlGaN/GaN HEMTs,and step bias stress can optimize the Schottky characteristics of devices,reduce the gate leakage current of devices,providing reference for the engineering application and performance optimization of AlGaN/GaN HEMTs devices.