Title :
Development of a High-k Pr
O
Sensing Membrane for pH-ISFET Application
Author :
Pan, Tung-Ming ; Liao, Kao-Ming
Author_Institution :
Dept. of Electron. Eng., Chang Gung Univ., Taoyuan
Abstract :
In order to develop a pH sensor having a good pH-sensing characteristic, electrolyte-insulator-semiconductor capacitors using a high-k P2O3 thin film as the sensing membrane were fabricated on silicon substrates by reactive radio frequency sputtering. The structural and morphological features of these films with annealing at various temperatures were studied by X-ray diffraction, atomic force microscopy, and X-ray photoelectron spectroscopy. The Pr2O3 sensing film after annealing at 900degC is suggested to the increase in the interfacial SiO2 and silicate formation, and the high surface roughness. Therefore, a physical vapor deposition Pr2O3 film is adopted as a new pH-sensing layer. The result produces a pH response of 52.9 mV/pH (pH=2-12), a hysteresis voltage of 17.5 mV (pH=7 rarr 4 rarr 7rarr 10 rarr 7), and a drift rate of 2.15 mV/h (pH=7 buffer solution).
Keywords :
annealing; chemical sensors; high-k dielectric thin films; ion sensitive field effect transistors; membranes; pH measurement; praseodymium compounds; silicon; sputtered coatings; Pr2O3; Si; X-ray diffraction; X-ray photoelectron spectroscopy; annealing; atomic force microscopy; electrolyte-insulator-semiconductor capacitors; high-k sensing membrane; pH sensor; pH-ISFET application; physical vapor deposition; reactive radio frequency sputtering; silicate formation; silicon substrates; surface roughness; temperature 900 C; voltage 17.5 mV; Annealing; Atomic force microscopy; Capacitive sensors; Capacitors; High K dielectric materials; High-K gate dielectrics; Semiconductor thin films; Sensor phenomena and characterization; Sputtering; Thin film sensors; Annealed at 900 $;^{circ}$C; Pr$_{2}$ O$_{3}$ ; drift rate; electrolyte-insulator-semiconductor (EIS); hysteresis; interfacial SiO $_{2}$ and Pr silicate formation; pH-ISFET; sensing membrane; sensitivity;
Journal_Title :
Sensors Journal, IEEE
DOI :
10.1109/JSEN.2008.2006259