<p>Chemical gas sensors can be used in a variety of applications such as process control, security systems and medical diagnosis. In the research for new functions and new sensing materials a “breadboard” would be useful. A technique that has been investigated for such a purpose is the grid-gate device which is a metal-oxide-semiconductor (MOS) based gas sensor. It is a MOS capacitor consisting of a passive grid-gate with depositions of sensing materials overlapping the grid. The measuring is carried out with a light addressable method called scanning light pulse technique (SLPT) which enables the detection of spatially distributed gas response.</p><p>A development of the grid-gate sensor would be to separate the sensing materials from the chip. In this thesis the aim was to see if this was possible by depositing the sensing material on a slide of micro pillars which was put on top of a biased grid-gate chip.</p><p>The test was made with palladium depositions in an ambient of synthetic air and 2500 ppm hydrogen, and the measuring technique was SLPT as for the preceding device.</p><p>The result of the test was that the new device showed a combined gas response of both charge content shift at flat-band voltage and at inversion voltages. The conclusion is therefore that the sensing material can be separated from the grid-gate chip and that the response will be caused by several mechanisms. The two-dimensional image response utilized for the preceding grid-gate device will instead be a multi-dimensional response consisting of the curve for the charge content shift at every measuring position.</p>

Chemical gas sensors can be used in a variety of applications such as process control, security systems and medical diagnosis. In the research for new functions and new sensing materials a “breadboard” would be useful. A technique that has been investigated for such a purpose is the grid-gate device which is a metal-oxide-semiconductor (MOS) based gas sensor. It is a MOS capacitor consisting of a passive grid-gate with depositions of sensing materials overlapping the grid. The measuring is carried out with a light addressable method called scanning light pulse technique (SLPT) which enables the detection of spatially distributed gas response. A development of the grid-gate sensor would be to separate the sensing materials from the chip. In this thesis the aim was to see if this was possible by depositing the sensing material on a slide of micro pillars which was put on top of a biased grid-gate chip. The test was made with palladium depositions in an ambient of synthetic air and 2500 ppm hydrogen, and the measuring technique was SLPT as for the preceding device. The result of the test was that the new device showed a combined gas response of both charge content shift at flat-band voltage and at inversion voltages. The conclusion is therefore that the sensing material can be separated from the grid-gate chip and that the response will be caused by several mechanisms. The two-dimensional image response utilized for the preceding grid-gate device will instead be a multi-dimensional response consisting of the curve for the charge content shift at every measuring position.