Preliminary evaluation of the influence of the temperature on the performance of a piezoresistive pressure sensor based on a-SiC film

Abstract

In order to evaluate the potential of amorphous silicon carbide (a-SiC) films for piezoresistive sensors applications, a pressure sensor has been developed based on this material. The deposition conditions and properties of a-SiC films deposited on thermally oxidized (100) Si substrates by two techniques enhanced by plasma, PECVD (plasma enhanced chemical vapor deposition) and RF magnetron sputtering, are briefly described and compared. Among the SiC films produced, we choose the nitrogendoped PECVD SiC film to fabricate the piezoresistors of the sensor. The structure of the sensor consists of six a-SiC piezoresistors, configured in Wheatstone bridge, on a SiO 2 / Si square diaphragm. The sensor was tested for applied pressure ranging from 0 to 12 psi and supply voltage of 12 V. A preliminary study of the influence of the temperature on the performance of the sensor was performed by experimental measurements and theoretical investigations.

Studies on SiC, DLC and TiO2 thin films as piezoresistive sensor materials for high temperature application

“…Regarding the thin film based piezoresistive sensors for harsh environments, in literature has been reported mainly strain gauges (Fraga et al 2010;Peiner et al 2006) and pressure sensors (Malhaire and Barbier 2003;Fraga et al 2011a;Wu et al 2001).…”

“…In particular, piezoresistive sensors based on thin films have been commonly developed because can be easily implemented using microfabrication processes and present the best relation between sensitivity and system complexity, which showing great advantages in term of device integration. In our previous works (Fraga et al 2010(Fraga et al , 2011a, we studied undoped and nitrogen-doped PECVD a-SiC thin films as alternative materials to replace the silicon piezoresistors in strain and pressure sensors for harsh environments. Here, we focused our attention on the piezoresistive properties of sputtered silicon carbide (SiC), diamond-like carbon (DLC) and titanium dioxide (TiO 2 ) thin films.…”

A simple thermo-compression bonding setup for wire bonding interconnection in pressure sensor silicon chip packaging

“…A change in pressure causes the diaphragm to flex, inducing a stress or strain in both the diaphragm and the buried resistors. The resistors values change in proportion to the stress applied and produce an electrical output (Crescini et al 2003;Fraga et al 2011).…”

Recent Developments on Silicon Carbide Thin Films for Piezoresistive Sensors Applications

“…Generally, the SiC thin-film piezoresistors are produced by RIE (reactive ion etching). Figure 9 illustrates two piezoresistive pressure sensors based on SiC films: one with six PECVD a-SiC thin-film piezoresistors, configured in Wheatstone bridge, on a SiO 2 /Si square diaphragm with Ti/Au metallization (Fraga et al, 2011b) and the other with phosphorusdoped APCVD polycrystalline 3C-SiC piezoresistors on Si 3 N 4 /3C-SiC diaphragm with Ni metallization (Wu et al, 2006). Another sensor type that has been developed based on SiC is the accelerometer.…”

“…Since then, it has been noted that the piezoresistive effect in semiconductor materials is highly anisotropic and exhibits a dependence on the dopant type, dopant concentration and crystalline orientation. (Fraga, 2010(Fraga, , 2011aFraga et al, 2011bFraga et al, , 2011c (Fraga, 2011c;Okoije 1998a).…”