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- Title
Role of Gate Oxide in AlGaN/GaN High-Electron-Mobility Transistor pH Sensors.
- Authors
Kang, B. S.; Wang, H. T.; Ren, F.; Hlad, M.; Gila, B. P.; Abernathy, C. R.; Pearton, S. J.; Li, C.; Low, Z. N.; Lin, J.; Johnson, J. W.; Rajagopal, P.; Roberts, J. C.; Piner, E. L.; Linthicum, K. J.
- Abstract
We report on a comparison of different gate oxides for AlGaN/GaN high-electron- mobility transistor (HEMT) pH sensors. The HEMTs show a linear increase in drain-source current as the pH of the electrolyte solutions introduced to the gate region is decreased. Three different gate oxides were examined, namely the native oxide on the AlGaN surface, a UV-ozone-induced oxide and an Sc2O3 gate deposited by molecular beam epitaxy. The Sc2O3 produced superior results in terms of resolution in measuring small changes in pH. The devices with Sc2O3 in the gate region exhibited a linear change in current between pH 3 and 10 of 37 µA/pH with a resolution of <0.1 pH over the entire pH range. In contrast, the native oxide devices showed a larger change in current, ~70 µA/pH, but with a degraded resolution of ~0.4 pH. Results for the UV-ozone oxide were intermediate in resolution, 0.2 pH. These HEMTs have promise for detecting pH changes in biological samples and can be readily integrated into a standard package for wireless data transmission.
- Subjects
OXIDES; MODULATION-doped field-effect transistors; FIELD-effect transistors; DETECTORS; ELECTROLYTE solutions; WIRELESS communications
- Publication
Journal of Electronic Materials, 2008, Vol 37, Issue 5, p550
- ISSN
0361-5235
- Publication type
Article
- DOI
10.1007/s11664-007-0298-y