Research On AlGaN / GaN HEMT Pressure Structure Design And Characteristic Simulation

In recent years,GaN as representative of the third generation of wide band gap semiconductor material, because of its excellent properties(high critical breakdown electric field, electron saturation velocity, high temperature, anti-radiation) become a hot topic,is rapidly developed in the field of high-frequency, high-power occasions. Due to polarization effects,III-V nitride compound AlGaN/GaN High Mobility Electron Transistors(AlGaN/GaN HEMTs) heterostructure without high doping can generate high mobility two-dimensional electron gas(2-DEG) to form a conductive channel.Although the AlGaN/GaN HEMT developed rapidly, but so far, its breakdown voltage is still far below its theoretical value.To solve this problem, this paper which is based on Sentaurus TCAD simulation software to establish an appropriate model through numerical simulation aim to optimize the distribution of the electric field components, reduce peak electric gate edge and improve the device breakdown voltage by numerical simulation.In this paper,the following aspects were studied:(1)Single gate metal field plate.the device with the gate field plate structure can change the distribution of the electric field in the channel, lower the first peak voltage,generate a second peak electric field, and the electric field distribution between the gate and drain is more even, then the breakdown voltage of the device is increased from 105 V to 300 V.(2)Ladder AlGaN barrier layer.According to the channel 2DEG concentration which is changed with AlGaN barrier layer thickness,design a new type of AlGaN/GaN HEMTs structure with Ladder AlGaN barrier layer,the impact of the length and height of the ladder on device performance is studied,When taking the optimal value, the breakdown voltage is 127.5 V, a certain improvement.Finally the new structure is obtained by adding gate field plate, its conduction resistance is 2.28 m?.2, the breakdown voltage is 379 V, the result is ideal.