Low temperature annealed amorphous indium gallium zinc oxide (a-IGZO) as a pH sensitive layer for applications in field effect based sensors
- Materials Science Programme, Indian Institute of Technology Kanpur, Kanpur-208016 (India)
The use of a-IGZO instead of the conventional high-k dielectrics as a pH sensitive layer could lead to the simplification of fabrication steps of field effect based devices. In this work, the pH sensitivities of a-IGZO films directly deposited over a SiO{sub 2}/Si surface were studied utilizing electrolyte-insulator-semiconductor (EIS) structures. Annealing of the films was found to affect the sensitivity of the devices and the device with the film annealed at 400 {sup o}C in N{sub 2} ambience showed the better sensitivity, which reduced with further increase in the annealing temperature to 500 {sup o}C. The increased pH sensitivity with the film annealed at 400 {sup o}C in N{sub 2} gas was attributed to the enhanced lattice oxygen ions (based on the XPS data) and improved C-V characteristics, while the decrease in sensitivity at an increased annealing temperature of 500 {sup o}C was attributed to defects in the films as well as the induced traps at the IGZO/SiO{sub 2} interface based on the stretched accumulation and the peak in the inversion region of C-V curves. This study could help to develop a sensor where the material (a-IGZO here) used as the active layer in a thin film transistors (TFTs) possibly could also be used as the pH sensitive layer without affecting the TFT characteristics, and thus obviating the need of high-K dielectrics for sensitivity enhancement.
- OSTI ID:
- 22584025
- Journal Information:
- AIP Advances, Vol. 5, Issue 6; Other Information: (c) 2015 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 2158-3226
- Country of Publication:
- United States
- Language:
- English
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