Effect of Annealed Si/Ti/Pt Hetero Structure on The Response Time and Signals of Hydrogen Sensors

Wahyu Widanarto (Department of Physics, Jenderal Soedirman University, Jl. Dr. Soeparno 61,53123 Purwokerto, Indonesia)
Farzand Abdullatif (Department of Physics, Jenderal Soedirman University, Jl. Dr. Soeparno 61,53123 Purwokerto, Indonesia)
Christoph Senft (Institut für Physik, Universität der Bundeswehr München, Werner-Heisenberg-Weg 39, 85579 Neubiberg, Germany)
Walter Hansch (Institut für Physik, Universität der Bundeswehr München, Werner-Heisenberg-Weg 39, 85579 Neubiberg, Germany)

Indonesian Journal of Physics (IJP)
Vol 22 No 1 (2011): Vol. 22 No. 1, January 2011

Titanium (Ti) and platinum (Pt) films deposited on p-doped Si electrode were incorporated as gas sensitive electrodes in Kelvin and Floating Gate Field Effect Transistor (FG-FET) systems. The films were annealed in oxygen at 800°C. SEM and EDX characterization methods were employed to study the surface of these films. Work function changes with respect to various hydrogen concentrations have been measured as a function of temperature and humidity. The results show that nano grains of titanium silicide (TiSi2) and Pt islands are formed after the annealing. Annealed TiSi2/Pt films are well suitable to significantly stabilize FG-FET based hydrogen sensor. The sensors can detect H2 in concentration range between 0.3% and 2% from room temperature up to 135°C. The response time is quite fast i.e. t90 ~ 43.2 seconds. An experiment on the stability has proved that signal pattern of the sensors remained stable one month after first conditioning.