A novel pH sensitive ISFET with on chip temperature sensing using CMOS standard process

A monolithic chip processing method is reported, which includes the ion sensitive field effect transistor (ISFET) of the pH sensor, p–n diode of temperature sensor and readout circuit using 0.5 μm double poly double metal (DPDM) standard CMOS product with UMC IC foundry company. We have designed a planar diffused silicon diode on a n-channel pH sensitive ISFET sensor to act as a temperature sensor for on-chip temperature measurement and compensation. Furthermore, the device integrated the dual sensors and readout circuit has the potential advantages of achieving, both the pH and temperature value display, with this process, ISFET’s temperature coefficient can be minimized.