Structural and sensing characteristics of Pr{sub}2O{sub}3 sensing membrane for pH-ISFET

摘要

Since Bergveld [1] reported on ion sensitive field effect transistors (ISFETs) for measuring ion concentrations in solutions, various kinds of chemical sensors have been developed. Silicon nitride films are the most popular material for sensing membrane due to easy process and high compatibility for CMOS integration [2]. However, it shows degradation of pH sensing characteristics from surface oxidation. Recently, high dielectric constant materials, such as A1{sub}2O{sub}3, Ta{sub}2O{sub}5, TiO{sub}2 and ZrO{sub}2 [3-5] were proposed as hydrogen ion sensing membrane for pH-ISFET to replace Si{sub}3N{sub}4 membrane because of their high sensitivity performance. The poor interface between the high-k material and silicon substrate, all sensing membranes must be deposited on the thermally grown SiO{sub}2 to improve the interface properties [6]. Nigro et al. reported [7] that praseodymium oxide film deposited on silicon substrate has shown a high-k value, low leakage current and negligible hysteresis in the C-V curve. In this paper, the physical and sensing properties of physical vapor deposition Pr{sub}2O{sub}3 dielectrics deposited on Si substrate were explored.