pH Sensing and Low-Frequency Noise Characteristics of Low Temperature (400 °C) p-Channel SOI Schottky ISFETs

Planar platinum silicide (PtSi) Schottky barrier (SB) p-channel silicon-on-insulator (SOI) ion-sensitive field effect transistors (ISFETs) have been fabricated at low temperature (400 °C) for biosensor applications. The use of PtSi not only eliminates the ion implantation process and associated high temperature annealing, it also simplifies the process complexity. Both dc and low frequency noise have been characterized. It is found that the SB p-channel SOI ISFET shows a high sensitivity of 55 mV/pH and a resolution limit of 0.0136% of a pH shift with 1 Hz bandwidth. All these suggest that the low temperature PtSi SB SOI ISFET is one of the promising candidates for biochemical detection.