Surface and near surface properties in silicon for sensing

Silicon-based cantilever structures fall into the category of Nano/Micro electro mechanical systems (MEMS) and due to their resonating nature as well as open to surface modification find extensive use as sensors, especially in biosystems. The electrochemically made porous silicon (PSi) has been promising in terms of immobilising biological molecules through its porosity and has led to improved biosensing applications. However, PSi loses its mechanical strength with porosity. The one-end cantilever sensors on the other hand are subject to non-uniform mass sensitivity. A novel Si-C-N and PSi-based pedestal cantilever structure have therefore been proposed which can result in improved biosensing. Finite Element modelling was done to show mass homogeneity for the system. The SiCN coatings were tested by nanoindentations depicting a strong substrate influence.