Research On High-power Gallium Oxide Schottky Barrier Diode And Junction Termination Technology

Gallium oxide(Ga2O3),as one of the rapidly developed semiconductor materials in recent years,has demonstrated its great potentials in high-power applications.compared to traditional semiconductor materials Ge and Si and the third generation of semiconductor materials SiC and GaN,Ga2O3 has a larger band gap and higher critical breakdown field strength.All the above properties make Ga2O3 SBD a potential candidate for next generation high power devices.Based on simulation and experiment,main investigations have been carried out are as follows:First,we design a novel edge termination with a groove for vertical Ga2O3 SBD and related numerical simulations are carried out using Silvaco-Atlas.The results show the groove termination can be significant to relieve the electric field enhancement at the junction corners and enhance the reverse breakdown voltage of the device Furthermore,SiO2 is the most appropriate choice as filling material in groove,and the maximum breakdown voltage of-2270V is achieved when the groove depth is 10 ?m and width is 8?m,a huge promotion compared with the Schottky diode(-515 V)without edge termination.Second,some research has been done on carrier transport across the Schottky junctions in Ga2O3 SBD.the Au/Ni/(3-Ga2O3 Schottky barrier diodes are fabricated on high-quality Ga2O3 substrate with the thickness of 15 and a lot of tests have been done.Test results indicate that the device shows satisfactory performances such as high current on-off ratio(1011),low specific on-resistance(2.1 mQ·cm2),high Schottky barrier height(1.33 eV)and high forward current density(>102A/cm2).Furthermore,we analyze the dependence of J-V characteristics on the temperature and prove that the forward carrier transport in Ga2O3 SBD follows the TFE mechanism by drawing the Richardson plot and calculating the characteristic tunneling energy E00.In addition,the calculated emission coefficient S suggest that the Poole-Frenkel emission is the dominant carrier transport mechanism under reverse bias.Third,we fabricate Ga2O3 SBD with argon-implanted edge termination structure.Test datas show that argon implantation doesn't cause any effect on the forward J-V characteristics of the device.The SBD presents excellent performance in forward electrical characteristics,such as low specific on-resistance(5.5m?·cm2),high Schottky barrier height(1.32 eV),excellent ideality factor(1.05)and high forward current density(133A/cm2 at 2V).More importantly,With edge termination structure,the breakdown voltage increases from 400V to 1010V,about a 150%increase.Moreover,we do some related simulation and make it clear that the maximum electric field in device at breakdown voltage(-1010V),that is the critical breakdown field strength of Ga2O3,is 6.84 MV/cm,which is quite closing to the theoretical value of Ga2O3.