The influence of the insulator surface properties on the hydrogen response of field-effect gas sensors

Abstract

Articles you may be interested inA Pt-Ti-O gate Si-metal-insulator-semiconductor field-effect transistor hydrogen gas sensor Effects of interface states and temperature on the C -V behavior of metal/insulator/AlGaN/GaN heterostructure capacitors Sulfur surface chemistry on the platinum gate of a silicon carbide based hydrogen sensorThe influence of mass transport processes on the response to gas mixtures of field-effect devices with large-area catalytic metal gatesThe hydrogen response of gas-sensitive field-effect devices is mainly due to trapping of atomic hydrogen on the insulator side of the metal-insulator interface of the metal-insulator-semiconductor ͑MIS͒ structure. Therefore an influence of the choice of insulator on the hydrogen response properties is expected. We have investigated this influence by producing MIS capacitors with four different insulators; SiO 2 , Al 2 O 3 , Si 3 N 4 , and Ta 2 O 5 . The results show that the choice of insulator influences the detection limit, the saturation concentration, and the saturation response. Furthermore, there is a strong correlation between the observed saturation response and the oxygen concentration of the insulator surface, as measured by Auger electron spectroscopy, which indicates that the trapping of hydrogen at the interface occurs at the oxygen atoms of the insulator surface. Finally, if the metal film is porous a catalytic oxidation of the insulator surface appears to be facilitated, which can increase the hydrogen response.

Catalytic metal-gate field effect transistors based on SiC for indoor air quality control

“…V DS is utilized to measure the response to the target gas (Lloyd Spetz et al, 2013b). The study, evaluation, and choice of the catalytic material and its support (the gate dielectric) are important because the electrical performance of FET sensor devices as well as the chemical reactions responsible for the gas response depend on the type and nanostructure of the sensing layer processed onto the device , in conjunction with the nature and quality of the gate insulator (Schalwig et al, 2002;Eriksson et al, 2005).…”

Basic physics of semiconductor hydrogen sensors

“…The surface concentration N g2 of the hydroxyl groups resulting from hydrogen atom adsorption on the centers occupied by О -ions can be described using Eq. (14). To this end, we replace N i by N i (А) and ΔЕ d by ΔЕ = Е d -Е a , where Е d and Е a are the activation energies of the hydrogen-atom desorption and adsorption processes, respectively.…”

“…(51) are greater than zero. In studies concerning the effect of hydrogen on the capacity-voltage characteristics of MOS-structures, it is assumed that Н 2 molecules dissociate into atoms on the palladium electrode and diffuse to the Pd-SiO 2 interface [13,14]. At the interface, a dipole layer is formed due to polarization of hydrogen atoms, and the layer electric field decreases the value of | U c |.…”

Gas-Sensitive Field-Effect Transistor Incorporating Polymer Layer and Porous Metal Electrode in the Gate Structure

“…(9,10) In previous reports, several models were proposed to explain the gas-sensing mechanisms of the catalytic gate field-effect devices. (11,12) The combination of cross-reactive sensing with pattern recognition methods is a promising way to identify gaseous target analytes and estimate their concentrations.…”

“…(17) Furthermore, properties of catalytic gate FETs can be tuned by several methods to achieve broad and differential responses. Several parameters are available for tuning the gas-responsive properties of catalytic gate field-effect devices, including the type of catalytic metal, (11,12) the type of insulating material, (10) and the operation temperature.…”