The optimized interface characteristics of β -Ga2O3 Schottky barrier diode with low temperature annealing

Abstract

A low temperature controlled annealing technique was utilized to improve the performance of vertical β-gallium oxide (β-Ga2O3) Schottky barrier diodes (SBDs) in this work. The nickel is diffused into Ga2O3, and NiO was formed at the interface between the anode and semiconductor generating p–n junction after low temperature annealing. Simultaneously, the trap state density of interface Ni/Ga2O3 as well as the carbon bonded with oxygen on the surface was reduced, which was proved by the capacitance and conductance measurements and x-ray photoelectron spectroscopic analysis, respectively. Combined the decreased saturation current density by three orders of magnitude from 1.21 × 10−6 to 9.27 × 10−8 and 5.12 × 10−9 A/cm2 and larger breakdown voltage from 220 to 270 V owing to the optimized interface and the formation of NiO, a low temperature annealing technique makes certain effective improvement for vertical β-Ga2O3 SBDs via interface engineering.

A review of metal–semiconductor contacts for β-Ga2O3

“…It is interesting that they found the Schottky barrier height of the device was changed with the variation of temperature, as shown in figure 6(c). This phenomenon is not surprising considering that Ni can be oxidized at a low temperature, thus affecting the homogeneity of the Ni/Ga 2 O 3 interface and altering the Schottky barrier height [59].…”

“…It is surprising that, although the contact of the four metals with Ga 2 O 3 should have shown Schottky characteristics, all four materials showed Ohmic contacts with Ga 2 O 3 after annealing, which can be attributed to the atom diffusion at the metal/Ga 2 O 3 interface. Hong et al [59] fabricated a Ni-Ga 2 O 3 contact and improved the quality through low temperature post-annealing. After post-annealing, they found that the I off of the device could decrease by two to three magnitudes, which can be attributed to the quality improvement of the Ni-Ga 2 O 3 contact and can be explained by the formation of NiO after annealing.…”

A Comprehensive Review on Recent Developments in Ohmic and Schottky Contacts on Ga2O3 for Device Applications

“…A controlled post low temperature annealing from 100 to 200 °C was observed to improve the performance of vertical Ni/β-Ga 2 O 3 SBDs on the HVPE-grown (001) β-Ga 2 O 3 epilayer . Through postannealing at 200 °C, leakage current decreased by three magnitudes from 1.21 × 10 –6 to 5.12 × 10 –9 A/cm 2 , and SBH increased from 1.07 to 1.14 eV.…”

“…However, R on and V on were increased from 4.81 mΩ·cm 2 and 0.70 eV to 8.96 mΩ·cm 2 and 0.80 eV, respectively. The improved device performance was attributed to the enhanced interface quality due to compensating the defects at the interface via Ni diffusion in Ga 2 O 3 and the formation of p-type NiO …”

“…The improved device performance was attributed to the enhanced interface quality due to compensating the defects at the interface via Ni diffusion in Ga 2 O 3 and the formation of p-type NiO. 205 Xian et al also studied the effect of different SC orientations on maximum achievable forward current density before failure and temperature distributions in the vertical SBDs. 204 As shown in Figure 17c, various size square and rectangular SCs with the long axis perpendicular to either the [100] or [010] crystallographic directions were fabricated.…”