CO _ NOx Sensor

Last crawled date: 1 year, 11 months ago

This CO _ NOx Sensor could be placed downstream a car filter to prevent a driver sickness.
It get a high of 20 mm for a diameter of 7mm.
A Carbon filter prevents a premature wear of the sensible part (wetness, dusts) and ensures a gaz particle separation for a better selectivity.

The sensible part (that is electricaly wired) is around 800µm high for a 6mm diameter. Take a look on the scheme for a detailled view.

----------------------------------------------------------------------------------------------------------------------------------------------
From Down to up:

- (Black) Wafer monocristal silicium (500µm)
- (Green) Dielectric membrane phosphorus oxynitride (3µm)
- (Red) Heat body polycristal silicium phosphorus doped (100 nm high, 300µm diameter)
- (Purple) Isolation coating silicium oxide (negligible high)
- (Blue) Circuits in platinum, chromium and titanium alloy (negligible high)
- (Green) Passivation coating (oxide protection)
- (Red sqared) Sensible layer in Tin Oxide (SnO2) (100 nm high, 300 µm long)

The sensible layer is heated at around 400-600°C by the heat body to alloys the oxidoreduction (SnO2 + CO = SnO + CO2) that will change the electrical conductivity that is measurable in the sensible layer.

Every single sensor need a callibration test.