Fabrication and Application of Ruthenium-Doped Titanium Dioxide Films as Electrode Material for Ion-Sensitive Extended-Gate FETs

• Published in: IEEE sensors journal 2009-03, Vol.9 (3), p.277-284
• Main Authors: Chou, Jung-Chuan, Chen, Cheng-Wei
• Format: Article
• Language: English
• Subjects: Annealing; Calcium; Calcium ion sensor; co-sputtering system; Detection; Electric variables measurement; Electrode materials; Electrodes; Fabrication; FETs; Field effect transistors; Gas detectors; Hydrogen; ion-sensitive extended gate field effect transistor (ISEGFET); ruthenium-doped titanium dioxide; Sensors; Sputtering; Titanium; Titanium dioxide
• ISSN: 1530-437X; 1558-1748
• DOI: 10.1109/JSEN.2008.2012221

A novel ruthenium-doped titanium dioxide (TiO 2 : Ru) film for pH detection is based on an ion-sensitive extended gate field effect transistor (ISEGFET) sensor. For the preparation of the TiO 2 :Ru sensing film, a specific processing for metal modification of TiO 2 thin film is deposited by a co-sputtering system. After thermal annealing treatment, material analysis of the sensing layer is measured by SEM, Hall measurement system and electrical detection system. The average sensitivity of TiO 2 :Ru for hydrogen ion detection is about 55.20 mV/pH (concentration range between pH1 and pH13). The effect of long-term drift for TiO 2 :Ru ISEGFET-based sensor is presented. Drift rate of the sensor for pH is 0.745 mV/h for 12 h. In order to prepare the calcium ion sensor, the sensing membrane of polymer materials is based on TiO 2 : Ru ISEGFET-based sensor by physical adsorption. The average sensitivity of the calcium ion sensor in the concentration ranging between 1 M and 1times10 -3 M CaCl 2 is about 29.65 mV/pCa.