The Characteristics of $\hbox{H}^{+}$ Ion-Sensitive Transistor Driving With MOS Hybrid Mode Operation

A chemical ion sensing using a gated lateral bipolar junction transistor (LBJT) has been performed. This letter reports the basic characteristics of the proposed device and the physical differences between a pure MOSFET-based device and gated LBJT, in giving consideration to an ion sensing. The operation in the linear region, the positive polarity between input bias and output signal, and the direct proportional relationship between pH value and output signal were achieved by the bias configuration and the proposed device using an unmodified standard CMOS process. When the base current is set at -50 muA and V
_RG
of -4 V, this device shows a sensitivity of 6.18 muA/pH.