Study of Nitride Thickness on Sensitivity IDEs Humidity Sensor Based on Graphene Oxide Sensing

An interdigitaged electrodes (IDEs) humidity sensor was patterned like a combs by lithography process based on silicon bulk substrate with different nitride thickness (50, 100 and 150 nm). This research studied an effect of thick nitride on sensitivity of IDEs humidity sensor based APTES adhesive layer with graphene oxide (GO) sensing material. The IDEs humidity sensor based on GO was comparatively examined all thick nitride conditions. Capacitance value of fresh IDEs humidity sensor shown not significant change all nitride thickness but it affected to sensitivity after GO coating due to high GO densified onto IDEs surface. Scanning Electron Microscope (SEM) was analyzed GO distribution and surface morphology. Raman spectroscopy clearly revealed the GO presence. The sensitivity from 50 to 80 %RH for optimal 100 nm thick nitride shows improvement to 2.78 and 1.27 times or 278.35% and 127.46% based on 50 and 150 nm thick nitride, respectively. Furthermore, the optimal condition of IDEs humidity sensor shows a little response and recovery times (11 and 7 sec), low hysteresis (3.21%), fine repeatability as well as high accuracy on long-term ability test. It clearly demonstrated for high sensitivity of nitride IDEs humidity sensor based on GO sensing film deposition.