Effect of the Al2O3 interfacial layer thickness on the measurement temperature-induced I–V characteristics in Au/Ti/Al2O3/n-GaAs structures

• Published in: Journal of materials science. Materials in electronics 2021-09, Vol.32 (17), p.22680-22688
• Main Authors: Turut, Abdulmecit, Karabulut, Abdulkerim, Efeoǧlu, Hasan
• Format: Article
• Language: English
• Subjects: Alumina-Titanium; Aluminum oxide; Bias; Characterization and Evaluation of Materials; Chemistry and Materials Science; Circuits; Current voltage characteristics; Diodes; Electrical measurement; Electronic circuits; Gold; Inhomogeneity; Materials Science; Optical and Electronic Materials; Optoelectronics; Thickness measurement; Thin films; Titanium; Vanadium
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-021-06753-1

We prepared the Au/Ti/Al 2 O 3 / n -GaAs MIS (metal/insulating/semiconductor) structures with and without Al 2 O 3 interfacial layer. The diode D1 has the interfacial layer thickness of 3 nm, and the diode D2 5 nm and diode D3 10 nm. We studied to obtain the high- or low-barrier-height devices depending on interfacial layer thickness for the availability of different opto-electronic circuit elements. We reported a zero-bias barrier height Φ b 0  value of 0.77 eV for the as-deposited Au/Ti/ n -type GaAs diode from the 300 K I–V measurements. We obtained the Φ b 0  values of 0.73, 0.94, and 1.11 eV for the D1, D2, and D3 MIS diodes at 300 K, respectively. The temperature-induced current–voltage measurements for the diodes were made in the temperature range of 50–320 K. The Φ b 0  value for the as-deposited and D1 diodes raised very slightly from 320 K down to 120 K, but it decreased sharply from 120 to 50 K. The temperature-induced current–voltage measurements for the diodes were made in the temperature range of 50–320 K. The Φ b 0  value for the D2 and D3 diodes decreased slightly from 320 K down to 120 K, but it decreased sharply from 120 to 50 K. The apparent low barrier height (BH) with decreasing temperature can be attributed to the fact that the current preferentially flows through the low BH with the temperature due to the BH inhomogeneity. The R s values for the as-deposited, D1, D2, and D3 MIS structures were determined as 130 Ω, 5.80 Ω, 101 Ω, and 216 Ω from the forward bias I–V curves at 300 K, respectively. The fact that the D1 and D2 samples have lower R s values than that of the as-deposited sample may be attributed to the fact that the Al 2 O 3 thin film improves the inhomogeneity of the Schottky interface.