Pd gate MOS sensor for hydrogen detection

摘要

The performance of Pd gate MOS hydrogen sensor was studied using C-V and G-V characteristics. The device was fabricated on p-type <100> (1-6 OMEGA cm.) silicon with thermal oxide layer of about 100AThe C-V and G-V responses of sensor were measured at different frequencies (1 kHz, 10 kHz, and 100 kHz) upon exposure to hydrogen (conc. 1-8 percent) at room temperature. It was observed that value of zero bias capacitance decreases with increase in frequency as well as hydrogen concentration. The inversion potential (V_(inv.)) and flat band voltage (V_(FB)) of the device approach higher values as frequency is reduced. Interface trap density (N_(it)) was also determined corresponding to the peak in the conductance curve, using a bias scan conductance method at fixed frequency. N_(it) was found to be decreasing with Increasing concentrations of hydrogen. The sensor showed better sensitivity at lower frequency.