Non-Stoichiometric Titanium-Oxide Gate Electrodes for EGFET Based pH Sensors

A compact pH measuring electrochemical sensor module was developed for Smart Multi-Well Plates (SMWP) applicable for highly parallelized cell culture analysis using incorporated Organon-Chip devices.A specific electronic architecture was designed and manufactured containing an extended gate field effect transistor as the transducer device.Electrochemical electrodes were functionalized using pH sensitive metal-oxides and applied as the gate material.The composition and the related pH sensitivity of differently deposited materials were characterized and the suitability of ALD-deposited, non-stoichiometric titanium oxide (TiO x ) for sensitive pH measurement was verified showing excellent responses close to the ideal Nernstian slope (59 mV/pH).