Response mechanism of SiC-based MOS field-effect gas sensors

Schalwig, J.; Kreisl, P.; Ahlers, S.; Müller, Gerhard

doi:10.1109/jsen.2002.806214

Cited by 70 publications

(56 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This voltage drop is influenced in the presence of various reducing and oxidizing gases. The response mechanism for hydrogen containing gases is mainly based on formation of polar hydroxide groups on the insulator surface at the metal insulator interface [4], [21]. Non-hydrogen containing dipole gases like CO and NO may also directly form dipoles or charged species on uncovered patches of the insulator [22], [23].…”

Section: A Sensor Devicementioning

confidence: 99%

See 1 more Smart Citation

Increasing the Selectivity of Pt-Gate SiC Field Effect Gas Sensors by Dynamic Temperature Modulation

et al. 2012

View full text Add to dashboard Cite

Abstract-Based on a diode coupled silicon carbide field effect transistor with platinum as catalytic gate material, the influence of dynamic temperature modulation on the selectivity of GasFETs has been investigated. This operating mode, studied intensively for semiconductor gas sensors, has only recently been applied to field effect transistors. A suitable temperature cycle (T-cycle) for detection of typical exhaust gases (CO, NO, C 3 H 6 , H 2 , NH 3 ) was developed and combined with appropriate signal processing. The sensor data was evaluated using multivariate statistics, e.g. linear discriminant analysis (LDA). Measurements have proven that typical exhaust gases can be discriminated in backgrounds with 0%, 10% and 20% oxygen. Furthermore, we are able to quantify the mentioned gases and to determine unknown concentrations based on training data. Very low levels of relative humidity (r.h.) below a few percent influence the sensor response considerably but for higher levels the cross interference of humidity is negligible. In addition, experiments regarding stability and reproducibility were performed.

show abstract

Section: A Sensor Devicementioning

confidence: 99%

“…It is interesting to note that the sensor reaction to NH 3 and C 3 H 6 changes its sign when oxygen is present. This can be explained by the sensing mechanism now being dominated by the reaction of the gas with adsorbed oxygen and spill-over effects [4], [21].…”

Section: B Influence Of Background Oxygenmentioning

confidence: 99%

Increasing the Selectivity of Pt-Gate SiC Field Effect Gas Sensors by Dynamic Temperature Modulation

et al. 2012

View full text Add to dashboard Cite

show abstract

“…It was reported that the sensing mechanism of hydrogen and non-hydrogen containing gases can be explained by spill-over effects of adsorbed oxygen [23]. Reducing gases like CO would react with adsorbed oxygen and thereby lower the density of oxygen on the surface.…”

Section: Introductionmentioning

confidence: 99%

Discrimination and quantification of volatile organic compounds in the ppb-range with gas sensitive SiC-FETs using multivariate statistics

Bur

Bastuck

Puglisi

et al. 2015

Sensors and Actuators B: Chemical

View full text Add to dashboard Cite

show abstract

“…Ammonia (NH 3 ), on the other hand, dissociates at the three phase boundaries (gas, metal, oxide) introduced by the porous gate, whereupon the protons cover the oxide surface or diffuse to the metal-oxide boundary (Lundström et al, 2007;Lloyd Spetz et al, 2013). In addition, M. Bastuck et al: Gas identification based on bias induced hysteresis Schalwig et al (2002) suggested a spillover of adsorbed oxygen ions as a possible explanation for the detection of nonpolar, (non-)hydrogen containing gases. The negatively charged oxygen ions on the gate oxide influence the electric field, hence the channel conductivity, and can be removed by reducing gases (e.g., CO; nitrogen monoxide, NO; or methane, CH 4 ) similar to the sensing mechanism of resistive type metal oxide gas sensors.…”

Section: Introductionmentioning

confidence: 99%

Gas identification based on bias induced hysteresis of a gas-sensitive SiC field effect transistor

Bastuck

Bur

Spetz

et al. 2014

J. Sens. Sens. Syst.

View full text Add to dashboard Cite

Abstract. In this work dynamic variation of gate bias is used on a gas-sensitive SiC field effect transistor ("GasFET") to optimize its sensitivity and increase its selectivity. Gate bias ramps introduce strong hysteresis in the sensor signal. The shape of this hysteresis is shown to be an appropriate feature both for the discrimination of various gases (ammonia, carbon monoxide, nitrogen monoxide and methane) as well as for different gas concentrations (250 and 500 ppm). The shape is very sensitive to ambient conditions as well as to the bias sweep rate. Thus, the influences of oxygen concentration, relative humidity, sensor temperature and cycle duration, i.e., sweep rate, are investigated and reasons for the observed signal changes, most importantly the existence of at least two different and competing processes taking place simultaneously, are discussed. Furthermore, it is shown that even for very fast cycles, in the range of seconds, the gas-induced shape change in the signal is strong enough to achieve a reliable separation of gases using gate bias cycled operation and linear discriminant analysis (LDA) making this approach suitable for practical application.

show abstract

Response mechanism of SiC-based MOS field-effect gas sensors

Cited by 70 publications

References 21 publications

Increasing the Selectivity of Pt-Gate SiC Field Effect Gas Sensors by Dynamic Temperature Modulation

Increasing the Selectivity of Pt-Gate SiC Field Effect Gas Sensors by Dynamic Temperature Modulation

Discrimination and quantification of volatile organic compounds in the ppb-range with gas sensitive SiC-FETs using multivariate statistics

Gas identification based on bias induced hysteresis of a gas-sensitive SiC field effect transistor

Contact Info

Product

Resources

About