Modeling and analyzing temperature-dependent parameters of Ni/β-Ga₂O₃ Schottky barrier diode deposited by confined magnetic field-based sputtering

Abstract

In this work, the temperature-dependent parameters of Ni/β-Ga2O3 Schottky barrier diode (SBD) were analyzed and modeled. The simulation is to elucidate the physical phenomenon behind this temperature dependence. At room temperature, the deviation of SBD parameters from the ideal case is due to the Schottky barrier height ( ϕ B ) inhomogeneity. A model is developed for this inhomogeneity in which an interfacial defected layer (IDL) is formed. Defects (extrinsic states) are related to plasma and Ar atom bombardment used in the confined magnetic field-based sputtering to realize the Ni Schottky contact diffusion in β-Ga2O3. Ni diffuses, upon annealing, to compensate defects in this IDL. It was found that the Schottky barrier height ( ϕ B ) and threshold voltage V Th decrease with increasing temperature. This decrease is related to intrinsic and extrinsic states (plasma and Ar bombardment). However, the ideality factor (η) increases which is related to the series resistance (R S) increase. The increase is related to the interfacial layer and nickel resistance increase with increasing temperature.

Physical Operations of a Self-Powered IZTO/β-Ga2O3 Schottky Barrier Diode Photodetector

“…SILVACO TCAD (Version 5.24.1.R, Silvaco Inc.: Santa Clara, CA, USA) was used to model the above structure. It solves the basic drift–diffusion semiconductor Poisson and continuity equations, which are [ 2 , 3 , 22 ]:…”

“…Poisson equation is given by [ 2 , 3 , 22 ]: where is the electrostatic potential, is the permittivity, and are the concentrations of the free holes and electrons, respectively, and is the density of the ionized traps .…”

“…The continuity equations for electrons and holes as defined in steady states are given by [ 2 , 3 , 22 ]: where and are the generation rates for electrons and holes, respectively, and and are the recombination rates for electrons and holes, respectively. and are the electron density and the hole current density, respectively, which are given in terms of the free electron and hole density ( and p ), electric field (E) and mobility ( and ) [ 25 ]: …”

“…Gallium oxide (Ga 2 O 3 ) is an oxide semiconductor material with a long, rich history [ 1 , 2 , 3 ]. It has an ultra-wide bandgap (UWBG) of ~4.8 eV, a high breakdown electric field of ~8 MV/cm, and a high saturation velocity of 1 × 10 7 cm/s, and these properties have brought Ga 2 O 3 to the fore once again [ 1 , 2 , 4 ].…”

“…Ga 2 O 3 has six polymorphs, i.e., and with β-Ga 2 O 3 being the most stable [ 1 ]. Unipolar devices based on β-Ga 2 O 3 , such as the metal–oxide–semiconductor field-effect transistor (MOSFET) [ 5 ], thin film transistor (TFT) [ 6 ], field emission (FE) [ 7 ], and Schottky barrier diode (SBD) [ 1 , 2 , 3 , 4 , 8 , 9 ], have been studied extensively. It is also used for deep ultraviolet (DUV) photodetectors (PDs) for solar-blind applications [ 10 , 11 ].…”