Research On Breakdown Mechanism Of Ga₂O₃ Power Device

Gallium oxide(Ga₂O₃)is a new type of ultra-wide band gap semiconductor material.Compared with third-generation semiconductors such as Ga N and Si C,it has outstanding advantages such as a wider band gap,higher critical breakdown electric field,and lower production costs.As a result,it has attracted great attention from the scientific and industrial circles on ultra-high voltage power electronic devices.With the rapid development of Ga₂O₃single crystal growth technology and the realization of high-quality epitaxy and controllable n-type doping technology,gallium oxide has important application prospects in the field of power electronics.In the current research,although the maximum breakdown electric field that a gallium oxide device can achieve has exceeded the theoretical limits of Ga N and Si C,it is still far from the theoretical limit of gallium oxide materials.In the paper,the Breakdown Mechanism of?-Ga₂O₃ MOSFET,SBD,and vertical Fin FET are studied by using Sentaurus TCAD.The results of our research are as follows:First,a simulation model of?-Ga₂O₃ MOSFET is established,and the reliability of the?-Ga₂O₃ model established in this paper is verified.The peak electric field distribution of?-Ga₂O₃ MOSFET and its causes were studied.The peak electric field of the device was optimized using a gate field plate.The optimal parameters of the gate field plate structure were obtained through research,and the breakdown voltage of the device was increased from367 V to 1126 V,an increase of 207%.The interval gate structure of?-Ga₂O₃ MOSFET was proposed for the first time to further optimize the breakdown characteristics of the device.The breakdown voltage of the device is further increased from 1126 V to 1270 V,an increase of 13%.Secondly,a simulation model of?-Ga₂O₃ SBD was established,and its forward characteristics and reverse breakdown characteristics were simulated.The distribution of the peak electric field of the device and its causes were studied.According to the causes of the peak electric field,the field plate structure and the stepped termination structure were used to optimize the device's peak electric field from two aspects.For the field plate structure,the optimal values of the field plate structure parameters are obtained.For the stepped termination structure,the optimal parameters of the structure were obtained,and the breakdown voltage of the device was increased from 354.1 V to 1030 V,an increase of190.9%.Thirdly,a simulation model of?-Ga₂O₃ vertical Fin FET structure is established,and the DC characteristics and breakdown characteristics of the device are simulated.The peak electric field distribution and the cause of the device are analyzed.The source field plate structure was used to optimize the peak electric field of the device,and the optimal parameters of the source field plate structure were obtained.The breakdown voltage was increased from 709.6V to 1192 V,an increase of 68.0%.In order to solve the problem of the degradation of the frequency characteristics of the device caused by the source field plate structure,a floating field plate structure of?-Ga₂O₃ vertical Fin FET was proposed for the first time to optimize the peak electric field of the device.The optimal parameters of the floating field plate structure were obtained.The device breakdown voltage was increased from 709.6 V to 1292V,an increase of 82.0%,without affecting the frequency characteristics of the device.