Research And Characteristic Simulation Of InAln/AlN/GaN Hemt

Among the third-generation semiconductors,GaN has lots of advantages as high breakdown voltage,mobility and saturation velocity and so on.Although the research of AlGaN/GaN HEMT has great development in the past years,the piezopolarization induced by the strain of the lattice mismatched heterostructure is still one of the key problems.At17%In-content InAIN can be grown lattice matched to GaN,with no piezoelectric stress, thereby improving device for the problem of reliability caused by heterojunction interface stress.But less study have been taken on InAlN/GaN heterostructure in past years, especially this is just the beginning in our state,so this paper will focus on this point.Firstly,InAlN/GaN HEMTs with the gate length of1.5μm,gate width of40μm and100μm are respectively designed and fabricated.InAlN/GaN HEMTs with air-bridge structure with gate length of1μm and gate width of2.5mm are also studied in preparation technology.Ohmic contact of the drain and source is made by Ti/Al/Ti/Au metallic system. Schottky contact of the gate is made by Ni/Au metallic system.Secondly, The DC performance of InAlN/GaN HEMT was tested.The peaktrans-conductance is200mS/mm when Vgs is-2V. The drain current is870mA/mm when Vgs is1V. The schottky barrier was measured by I-V and C-V methods. By measuring the Schottky barrier C-V characteristics, given the interface defect charge density, and analyze Abnormity output characteristics curve.Finally, simulation on the two-dimensional GaN-based HEMT device parameters has been carriered out with electrical characteristic and thermal characteristic.The main research work and results are as follow:1. Study the polarization of GaN-based heteroj unction effect in the role of the structures of GaN-based HEMT.2. Study the GaN-based heteroj unction2DEG concentration with the variation of structural parameters, especially the impact of barrier layer thickness d and the barrier layer In content of devices.3. Determine the simulation model of device and the the basic setting method of the structure and Analyze the changes in the structure of the device in the effect of DC characteristics.4. Make further analysis of GaN based HEMT thermal properties, detail study from the thermal effect on the electrical properties and the thermal profile distribution of device.