Optimization of platinum adhesion in electrochemical etching process for multi-sensor systems

This paper presents optimized process conditions to overcome the problem of poor adhesion between platinum (Pt) metal layer and substrates in an electrochemical etching process required for forming porous silicon. Good Pt adhesion on silicon and silicon nitride substrate is obtained by respectively, applying 20 nm Ta and 20 nm/20 nm tantalum/polysilicon layer between them to improve adhesion and prevent the diffusion of Pt to the substrates. The best anneal conditions for the metallization systems are 590 °C, 30 min, 18 °C/min in a N2 ambient furnace. The optimized process is used for the realization of a Pt metallization-based multi-sensor system.