The reverse bias current–voltage–temperature (I–V–T) characteristics of the (Au/Ti)/Al2O3/n-GaAs Schottky barrier diodes (SBDs) in temperature range of 80–380 K

Abstract

We analyzed current conduction mechanisms (CCMs) of the (Au/Ti)/Al2O3/n-GaAs (MIS) type SBDs in the wide temperature range (80–380 K) by 30 K steps using reverse bias current-voltage (IR–VR) characteristics. In general, the values of barrier-height (BH) obtained from the forward bias current–voltage (IF–VF) and reverse bias current-voltage (IR–VR) characteristics increase with increasing temperature and this change is in-agreement with the reported negative-temperature coefficient bandgap of semiconductor (α = ΔEg/ΔT) or BH for ideal SDs. However, the change in BH at lower temperatures becomes more pronounced. The value of BH obtained from the IR–VR data is lower than that obtained from IF–VF especially under room temperatures. The necessary barrier height (Φt) for electron emission from the trap state was obtained from the ln (IR) − E0.5, (E = VR/d), plot as 1.25 eV to (at 80 K) 0.91 eV (at 380 K), respectively. This change in the Φt with temperature is in agreement with the reported α value of the Eg for GaAs. The reverse leakage current mechanism in this study was assessd for various temperatures using Schottky emission (SE), Poole–Frenkel emission (PFE), Trap-Assisted Tunneling (TAT), and ohmic conduction mechanisms. The evaluation of the IR–VR characteristics shows that the ohmic and TAT are the most dominant conduction mechanisms rather than others.