Pt-Ti-O gate silicon-metal-insulator-semiconductor field-effect transistor hydrogen gas sensors in harsh environments

摘要

The influence of radiation damages to developed hydrogen gas sensor chips from gamma-rays (Co-60) and/or X-rays (synchrotron radiation) is manageably avoided for sensor operations even at extremely high integral doses such as 1.8 and/or 18 MGy. Platinum-titanium-oxygen (Pt-Ti-O) gate silicon-metal-insulator-semiconductor field-effect transistor (Si-MISFET) hydrogen gas sensors can work stably as hydrogen sensors up to about 270 degrees C and also show environmental hardness as follows: When nitrogen-diluted 10-ppm hexamethyldisiloxane (HMDS) was exposed to the sensor FETs for 40 min at a working temperature of 115 degrees C, large sensing amplitude (Delta V-g) changed little within repetition errors before and after HMDS exposures. The variations of Delta V-g among relative humidity of 20 and 80% are very small within +/- 4.4% around 50% under 40 degrees C atmosphere. The Pt-Ti-O sensors have been found to show large Delta V-g of 624.4 mV with sigma V-g of 7.27 mV for nine times repeated measurements under nitrogen-diluted 1.0%-hydrogen gas, which are nearly the same values of 654.5 mV with sigma V-g of 3.77 mV under air-diluted 1.0%-hydrogen gas. (C) 2016 The Japan Society of Applied Physics