Role of interfacial oxide layer thickness and annealing temperature on structural and electronic properties of Al/Ta2O5/TiO2/Si metal–insulator–semiconductor structure

Autor: B. Purusottam Reddy, S. Uthanna, Harish Sharma Akkera, N. Nanda Kumar Reddy, Si-Hyun Park, M. Chandra Sekhar, V. Rajendar
Rok vydání: 2017
Předmět:
Zdroj: Journal of Alloys and Compounds. 718:104-111
ISSN: 0925-8388
Popis: In this study, we investigated the structural and electrical properties of TiO 2 /Ta 2 O 5 stacks prepared using DC reactive magnetron co-sputtering for as-deposited films and films annealed at 700 °C. X-ray diffraction studies revealed that the as-deposited films were amorphous, whereas those annealed at 700 °C were polycrystalline with mixed phases of TiO 2 and β-phase Ta 2 O 5 . The presence of mixed phases of TiO 2 and β-phase Ta 2 O 5 was also confirmed by Fourier-transform infrared spectroscopy. The optical band gap of the TiO 2 films was 3.46 eV for the as-deposited films and decreased to 3.35 eV with increasing Ta 2 O 5 layer thickness on TiO 2 . The films annealed at 700 °C showed a decrease in band gap to 3.32 eV for TiO 2 , and this value further decreased to 3.15 eV with increasing Ta 2 O 5 layer thickness on TiO 2 . Furthermore, we investigated the electrical properties of the sputtered TiO 2 /Ta 2 O 5 stacks fabricated on a metal–insulator–semiconductor (MIS) Al/Ta 2 O 5 /TiO 2 /p-Si Schottky diode. We studied the variation of the fundamental Schottky barrier characteristics (ideality factor, Schottky barrier, and series resistance) for a diode prepared using reactive magnetron sputtering with TiO 2 /Ta 2 O 5 as a thin insulating layer at the Al/p-type Si interface with different thicknesses at both room temperature and 700 °C. Improved electrical characteristics were observed for the annealed Al/Ta 2 O 5 /TiO 2 /p-Si MIS Schottky structure compared with those of the as-deposited structure.
Databáze: OpenAIRE
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