Study On Mechanically Exfoliated Ga₂O₃ Schottky Diode

In this paper,gallium oxide materials were prepared by mechanically exfoliating,and a variety of different Schottky diode devices were fabricated.A series of electrical tests are carried out on the Ga₂O₃ Schottky devices and the test results are analyzed.Through the I-V characteristics of different devices in the temperature range of 300 K-473 K,it is found that the I-V characteristics of devices change with the change of operating temperature.At the same time,it is demonstrated that the Schottky barrier of diodes fabricated by mechanically exfoliated gallium oxide materials is not uniform.In this paper,hundreds of nanometers and one hundred microns of gallium oxide thin films were prepared by mechanically exfoliating,and the parallel,vertical and oxygen annealed gallium oxide Schottky devices were fabricated.Among them,the parallel device with thickness of 100 nm shows a very obvious UV response,and the maximum light dark current ratio is 7570 times for the UV light of 253.7 nm.The response of the device to UV light is significantly higher than that of the other two devices,which is mainly due to the combination of the lateral device without electrode shielding and the mechanically exfoliated material surface states.The band bending is caused by the surface state collecting charge,while the band flattening is caused by the combination of the new carrier pair which excited by the ultraviolet light,and the Schottky barrier is reduced,so the current is increased obviously.The vertical Schottky diode show obvious rectifying characteristics.The barrier height of the device is 0.86eV,and the ideal factor is 2.35.The barrier height of the device is low and the ideal factor is a little high,which is mainly due to the inhomogeneity of Schottky electrode and the poor quality of the interface of the exfoliated sample.The Schottky electrode made of gallium oxide is optimized.The vertical Schottky device with optimized technology has batter electrical characteristics.The barrier height is 1.17 eV,and the ideal factor is 1.06 at 450 K.It's very close to the ideal value of 1.At the same time,the device shows better Schottky barrier uniformity and better leakage current control.The Richardson constant of the calculator is 33.08 A/cm²k²,very close to the theoretical value of 41.11 A/cm²k².The electrode activation area of the device is about 80%,which is much larger than the electrode activation rate of less than 1%before process optimization.In addition,the vertical structure Schottky devices made of oxygen annealed gallium oxide were tested.It is found that the leakage current of the device is lower than that of the device without annealing,but the carrier concentration of the material has no obvious change.It is concluded that the Schottky diodes with mechanically exfoliated gallium oxide have good rectifying characteristics.Among them,the parallel device has obvious response to UV light,while the vertical device can control the leakage current growth well.If gallium oxide with low carrier concentration can be obtained,it may have some advantages in the field of radiation detector.In addition,oxygen annealing can effectively reduce the oxygen vacancy defects of gallium oxide materials,but the carrier concentration of unintentionally doped gallium oxide materials may not be caused by oxygen vacancy defects.