Enhanced Sensing Performance of MISiC Schottky-Diode Hydrogen Sensor by Using HfON as Gate Insulator

MISiC Schottky-diode hydrogen sensor with HfON gate insulator fabricated by NO nitridation is investigated. The hydrogen-sensing characteristics of this novel sensor are studied by doing steady-state and transient measurements at different temperatures and hydrogen concentrations using a computer-controlled measurement system. Experimental results show that this novel sensor can rapidly respond to hydrogen variation and can give a significant response even at a low H ₂ concentration of 48-ppm, e.g., a sensitivity of 81% is achieved at 450°C and 2.5 V, which is two times higher than its HfO₂ counterpart. The enhanced sensitivity of the device should be attributed to a remarkable reduction of the current of the sensor before hydrogen exposure by the NO nitridation because the NO nitridation can passivate the O vacancies in the insulator and facilitate the formation of a SiO₂ interlayer to suppress the leakage current associated with high-k materials.