Modeling a Ni/β-Ga₂O₃ Schottky barrier diode deposited by confined magnetic-field-based sputtering

Abstract

In this work, a detailed numerical simulation is carried out to model the current–voltage characteristics of a nickel/β-Ga2O3 Schottky barrier diode at different temperatures. These SBDs are produced using confined magnetic-field-based sputtering to deposit the nickel (Ni) Schottky contact of the diode. This method reduces the thickness of the defect area created by plasma and argon bombardment, and consequently, the electrical characteristics are less affected by temperature changes or annealing (i.e. the device is more stable). During annealing, Ni diffuses into β-Ga2O3. A model for this diffusion is proposed in this work, in which Ni diffusion reduces the defects produced by plasma and argon bombardment by filling the Ga vacancy. Furthermore, Ni diffusion produces a new interfacial compound, namely (N i x G a 1 − x ) 2 O 3 at the interface between the Ni and the β-Ga2O3. This new compound layer has different properties than those of β-Ga2O3, in particular, those of the bandgap and the affinity. Finally, the temperature-dependent current-density–voltage (J–V) characteristics are simulated, taking the proposed model into account. A good agreement with measured values is achieved, especially at low forward voltages, which demonstrates the soundness of the proposed model.

Control of Ni/β-Ga2O3 Vertical Schottky Diode Output Parameters at Forward Bias by Insertion of a Graphene Layer

“…The Poisson equation is given by [ 2 , 21 ]: where is the electrostatic potential, is the permittivity, and are the free holes and electron concentrations, respectively, and is the trap’s ionized density .…”

“…The continuity equations for electrons and holes are defined in steady states by [ 2 , 21 ]: where and are the generation rates for electrons and holes, respectively, and are the recombination rates for electrons and holes, respectively, and are the electron and hole current densities, respectively, which are given in terms of the quasi-Fermi level ( and ) and mobility ( and ) as [ 2 , 21 ]: …”

“…Gallium oxide (Ga 2 O 3 ) is a new oxide semiconductor material with a long and rich history [ 1 , 2 ]. Pioneer studies were performed in the 1960s but were almost forgotten for about three decades.…”

“…Ga 2 O 3 has six polymorphs: α, β, γ, δ, ε and k, with β- being the most stable [ 4 ]. Furthermore, it can be grown directly from the melt at a low cost and allows for large-scale production compared with GaN, InGaN, and SiC [ 1 , 2 , 4 ]. However, this material has a problem with developing a stable p-type [ 2 , 5 , 6 , 7 ].…”

“…Furthermore, it can be grown directly from the melt at a low cost and allows for large-scale production compared with GaN, InGaN, and SiC [ 1 , 2 , 4 ]. However, this material has a problem with developing a stable p-type [ 2 , 5 , 6 , 7 ]. As a result, its use in bipolar devices is limited to a heterojunction with other p-type materials such as NiO [ 8 , 9 ] and Cu 2 O [ 10 ].…”