[2020] Ammonia & humidity sensors

Measurement of ammonia is extremely important in a number of industries. In the automotive industry it is required for diesel motors. The pig industry requires ammonia sensors to optimise ventilation in the winter. Ammonia has be defined in the US as a dangerous gas, and yielding more applications in pollution control.

Ammonia vapour is extremely corrosive and will attack silicon. Adding water vapour increases this problem. Moving to SiC is one solution. SiC is extremely robust and can survive ammonia for long periods, also at high temperature. By making the SiC porous, we can adjust the structure to achieve different sensitivities for ammonia and humidity. From this we can calculate both.

Assignment

The main part of this project it to optimise the process. The electrochemical etching, performed in EKL, will need to be adjusted to achieve the optimum structure of the pores. Once the SiC has been deposited on the front side and metal on the back, the devices are etched in HF. The main parameter to be changes is the current density.

Measurements can then be made to establish the sensitivity for both parameters. At a later stage electrodes will need to be designed. The project contains fabrication processes, measurement and design optimisation.

Contact

Last modified: 2020-07-06