Influence of gridded gate structure on gas sensing behavior of hydrogen

A gridded Pt/SiO2/Si MOS sensor for hydrogen detection has been fabricated on p-type ⟨100⟩ Si wafer having resistivity (1–6 Ω cm). The SiO2 and Platinum (Pt) gate thickness were kept about 10 nm and 35 nm. The performance of Pt gate MOS sensor was evaluated through C-V characteristics (capacitance v...

Full description

Saved in:
Bibliographic Details
Published in:Journal of applied physics 2014-05, Vol.115 (20)
Main Authors: Kumar, Vinod, Mishra, Sunny, V. N., Dwivedi, R., Das, R. R.
Format: Article
Language:English
Subjects:
Applied physics
Capacitance
Density
Electric potential
Gas sensors
Platinum
Porosity
Sensors
Silicon dioxide
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:A gridded Pt/SiO2/Si MOS sensor for hydrogen detection has been fabricated on p-type ⟨100⟩ Si wafer having resistivity (1–6 Ω cm). The SiO2 and Platinum (Pt) gate thickness were kept about 10 nm and 35 nm. The performance of Pt gate MOS sensor was evaluated through C-V characteristics (capacitance vs voltage) upon exposure to H2 (250 ppm–4000ppm) at different frequencies (25 kHz and 50 kHz) in a closed chamber at air ambient atmosphere. The capacitance of the sensor decreases with increase in frequency as well as H2 gas concentration. The flat band voltage characteristics have been evaluated at different frequencies and concentrations. It decreases as the frequency and concentration of gas both increases. The maximum flat band voltage change was observed −0.6 V at 25 kHz. The sensor exhibits better sensitivity (∼88%) at low frequency (25 kHz). The high response of sensor is attributed to the side wall diffusion, increase in surface area caused by inner side wall and increase in porosity, increase in fixed surface state density, spill-over mechanism and change in interface state density on exposure of gas along with the formation of dipole layer.
ISSN:0021-8979
1089-7550
DOI:10.1063/1.4879875