| In recent years,gallium oxide(Ga2O3)material has been studied and recognized by more and more people as an ultra-wide band gap semiconductor material.With its large energy band gap(4.9 e V),high theoretical breakdown electric field and excellent photoelectric properties,the Schottky barrier diode(SBD)prepared on the gallium oxide material can theoretically obtain good device characteristics,so it has gradually become a popular research object.This article mainly conducts basic research work on Schottky barrier diodes with different terminal structures from theoretical simulation and experimental aspects,and obtains the following conclusions.First,a vertical gallium oxide Schottky barrier diode with floating metal ring was designed by the semiconductor simulation software Silvaco TCAD,and its basic electrical characteristics were obtained through simulation calculations.In addition,the structural parameters of the floating metal ring are optimized through simulation and analysis of the electric field distribution.Based on previous experimental experience,it is found that when the distance from the metal ring to the anode(LS)is 3(?)m and the width of the floating metal ring(LR)is 4(?)m,the theoretical breakdown voltage of the device is the highest.Second,based on the previous simulation results as a reference,we prepared several groups of vertical gallium oxide Schottky barrier diode with different structural parameters of floating metal ring.The devices showed good characteristics through the electrical test with Ion/off,turn-on voltage,ideality factor,Schottky barrier height and on-resistance of 108,1.0V,1.18,1.10 e V,and 6.1 m?·cm2,respectively.In addition,we focused on testing and studying the reverse characteristics of the devices.The test results showed that the breakdown voltage of regular gallium oxide Schottky barrier diodes was 119 V.And as LSincreased from 1(?)m to 4(?)m,the breakdown voltages of Schottky barrier diodes reached160 V,175 V,194 V,and 188 V,respectively.The breakdown voltage relatively improved by34.45%,47.06%,63.03%and 57.98%.Therefore,the optimal structure parameters of the Schottky barrier diode with floating metal ring are LS=3(?)m and LR=4(?)m.Third,gallium oxide Schottky barrier diode with a vertical small bevel terminal structure was designed by using semiconductor device simulation software.The device showed good electrical characteristics through simulation calculations.The breakdown voltage of the device was as high as 850V with a small on-state resistance of 2.7 m?·cm2.Compared with regular gallium oxide Schottky barrier diodes,the breakdown voltage of the former increased from 250 V to 850 V with significantly improvement of 240%.Fourth,according to the results of the previous simulation,vertical beveled fluorine plasma treatment gallium oxide Schottky diode was fabricated by experiment.The results showed that the device had excellent performance with Ion/off,turn-on voltage,on-state resistance,ideality factor and barrier height of 1010,0.7 V,2.9 m?·cm2,1.05 and 1.12 e V,respectively.The reverse breakdown voltage is as high as 890 V,which is 256%higher than the regular structure diode prepared on the same substrate.Fifth,vertical gallium oxide Schottky barrier diode with field plate edge termination was designed by Silvaco TCAD.And silicon nitride material with high voltage stability and high resistivity was chosen as the dielectric material under the field plate.Preliminary calculations showed that the device had excellent electrical characteristics.The devices had breakdown voltage of 777 V with on-state resistance of 4.6 m?·cm2.Then the structural parameters of the devices were further optimized.When the length of the field plate overlap is 4(?)m,and the growth thickness of the dielectric layer is 400 nm,the breakdown voltage of the device is up to 870 V,which is 166%higher than that of regular Schottky barrier diodes.Sixth,based on the gallium oxide Schottky barrier diode with field plate terminal structure,we designed a new type of trench field plate gallium oxide Schottky barrier diode by Silvaco TCAD.Through theoretical calculation of the basic electrical characterisics,it was concluded that the new trench gallium oxide Schottky barrier diode had good device performance.The on-state resistance of the device was as small as 4.9 m?·cm2,indicating low power consumption when it is working.The turn-on voltage of the diode was 0.8 V,and the breakdown voltage after structural optimization reached as high as 1.2 k V with extremely low leakage current. |
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