The effect of trapping sites introduced by 1 MeV proton irradiation on the reverse current recovery time in Ga2O3-based Schottky diodes

Abstract

The reverse current recovery time is an important parameter of diodes, fast rectifiers and transistors which determined their high-frequency properties and area of application. Defects in the structure may sufficiency reduce the cutoff frequency and lead to overheating. The reverse recovery of the low currents in the α- and β-Ga2O3 Schottky diodes was measured and analyzed in this study. The reverse recovery time in the β-Ga2O3-based Schottky diode is limited mainly by the relaxation of the RC-circuit formed by the equivalent diode circuit and can be very low (20 nsec in this case). Irradiation can introduce some defects in the structure, which may act as deep levels and prolong the relaxation. We have demonstrated experimentally that increasing serial resistance of the circuit lead to an increase in the reverse recovery time. But we can point an additional part of relaxation that can be attributed to the emission from deep levels in the forbidden gap of the semiconductor. It is shown that prolongation increases with the reverse recovery time but saturates. In the α-Ga2O3-based structures the reverse recovery time measured after proton irradiation was 6 μsec, twice as high than it can be expected from RC-circuit relaxation time. These deep levels can be associated with interstitial oxygen atoms. The results obtained can be used to improve the technology of crystal growth to produce Schottky diodes with a high boundary frequency.