Capacitor sensors

SiC capacitor sensors have demonstrated gas-sensitivity to gases such as hydrogen and hydrocarbons [21, 46, 68] up to a maximum temperature of 1,000°C [1, 68]. Devices that can be operated both as MOS capacitors (reverse bias) and as Schottky diodes at temperatures greater than 490°C have also been demonstrated (see Section 2.4.2) [10]. These devices showed sensitivity to combustible gases such as propane, propylene, and CO and were tested at temperatures up to 640°C. 

Schalwig et al. have tested the feasibility of using a SiC MOS capacitor sensor containing a contact metal of 40-nm TaSi plus 45-nm Pt to detect NO and HC after the catalytic converter. This was carried out by simulating lean burn engine exhausts [116]. It was observed that the sensor signal increased for NO detection and decreased for HC detection. This could permit this sensor to be used in a sensor array to differentiate these two gases. 

A chemical species in the environment of a C-I-S capacitor sensor structure can interact with the device and thereby modify its double layer in the same four ways it can interact with the double layer of a C-S or C-I-S diode sensor. These four mechanisms need to... 

Si capacitor sensor response is enhanced by raising the operating temperature. Here data are shown for room temperature and 160°C. 

The effect of the presence of water vapor on hydrogen detection at room temperature for C-I-S capacitor sensors is seen in Figure 16. The data show that water vapor tends to reduce the sensitivity to... 

The first question to ask when comparing various diode and capacitor sensor structures is how do their sensitivities compare. This question is answered for several hydrogen sensing structures in Table V. 

Thus, zeolite-coated IDCs have been tested for sensing n-butane [317] and also, NH3, NO, and CO [318,319] on Na-Y and NaPtY zeolite-based sensors at temperatures high enough to where chemical reactions may also occur (above 200°C). The response time is of the order of seconds and the cross-sensitivity to water is small at high temperatures, at which no water condensation occurs in the zeolite-pore system. Under certain conditions, selectivity of these reactive chemical sensors is remarkable. Thus, the detection of 10 ppm of n-butane with a NaPtY interdigitated capacitor with no response to CO and H2 has been reported [318]. Similarly, Moos et al. [320] described a ZSM-5 based capacitor sensor with on-chip heating for temperatures up to 450°C capable of detecting NH3 with no cross-sensitivity to CO, hydrocarbons, and O2. 

High-Tc- superconductors Dielectrics Thin film/bulk devices capacitors, sensors, phase shifters, dynamic RAMS YB32C U307, BsTi03... 

Electrical and electronic parts, various types of connectors (board-to-board connectors, flexible printed circuit connectors, card connectors, flash memory connectors, optical connectors), various types of sockets (PGA sockets, ZIF sockets, SIMM sockets, RIMM sockets, SO-DIMM sockets), relay casings, switches, quartz oscillators, piezoelectric elements, capacitors, sensors, coil bobbins, optical sensors, and encapsulant... 

Barium titanate, strontium titanate and other perovskite ceramics Capacitors, sensors, embedded electronics, security inks... 

---