改良型五氧化二鉭與氧化銥薄膜氫離子感測電極之研究

Abstract

離子選擇性場效電晶體(ISFET, Ion Sensitive Field Effect Transistor)最早由Piet Bergveld 於1970 年提出，為擁有離子選擇與場效電晶體元件特性的微型化學感測器，且符合 MOSFET 之製程技術而可以大量生產。 以射頻磁控濺鍍法將氧化銥薄膜鍍於白金電極上做為氫離子感測膜，並接著濺鍍一層五氧化二鉭薄膜做為離子選擇膜包覆氧化銥，所製成之氫離子感測電極對氫離子具有單一選擇性，在pH2-12間為線性工作區其靈敏度為56.03mV/pH，具有良好的電位穩定性和再現性等優點，對溶液pH變化的平均反應時間為20秒，可耐酸鹼腐蝕且壽命可長達4個月以上。

ISFET, Ion Sensitive Field Effect Transistor, was first proposed by Piet Bergveld in 1970 to have ion sensitivity and field-effect transistor components of micro-chemical sensors. The ISFET is in accordance with the process technology, MOSFET, and can be mass-produced. Using the RF magnetron sputtering method, iridium oxide is electroplated onto the platinum electrode as a hydrogen ion sensors film. Then a thin layer of tantalum oxide film is sputtered on the electrode as an ion-selective membrane that coats the iridium oxide. This will produce a hydrogen ion sensing electrode that is selective toward hydrogen ions with linear work areas that are in between pH2 and pH12, and a sensitivity of 56.03 mV / pH. The hydrogen ion sensing electrode has advantages of good stability and reproducibility, and an average response time of 20 seconds to changes in the pH of the solution. It is resistant to acid corrosion, and has a lifetime that is at least four months.