Author_Institution :
Dept. of Microelectron. Eng., Nat. Kaohsiung Marine Univ., Kaohsiung, Taiwan
Abstract :
As the growth temperature, annealing temperature, and annealing time of InN sensing film of InN/InNO/In2O3/In/SiO2/Si humidity sensor were, respectively, adjusted at 400°C, 400°C, and 15 min, the sensing surface possesses obvious particles of nanometer scale. The particle size of InN sensing film was estimated about 65 nm which realized the quantum effect of InN sensing film for the humidity sensing performance in chemistry. The designed p-n InN/InNO/In2O3/In/SiO2/Si structures of humidity sensor in this paper contained three different buffer layers (indium layer, InNO layer, and In2O3 layer) which also revealed the negative differential resistance effect with peak current density of 2.8 kA/cm2 and peak-to-valley current ratio of 1.93 for quantum resonant microwave performance in physics. The periods of water molecular adsorption and desorption are ~600 and 580 s, respectively. The sensing resolution of adsorption and desorption is defined by resistance variation per second. The response sensitivity (SR) of adsorption and desorption are ~0.25 mQ/s (0.1%RH/s) and 0.41 mQ/s (0.1%RH/s), respectively. The InN/InNO/In2O3/In/SiO2/Si humidity sensor revealed the sensing sensitivity of 6 × 10-3 ohm/% RH. The InN/InNO/In2O3/In/SiO2/Si humidity sensor also revealed the resistive cutoff frequency ( fr) and the selfresonant frequency (fSR) of microwave device reached as 1.6 MHz and 70 GHz, respectively. Microwave transmission property of p-n InN/InNO/In2O3/In/SiO2/Si humidity sensor reached as gigahertz frequency range can transfer the humidity signal from patient to monitoring station via high frequency wireless communication from one device. InN/InNO/In2O3/In/SiO2/Si humidity sensor can be, therefore, applied in w- reless microwave transmission of human body sensing signal.
Keywords :
III-V semiconductors; adsorption; annealing; buffer layers; current density; desorption; electric resistance; elemental semiconductors; humidity sensors; indium; indium compounds; microwave spectra; nanostructured materials; p-n junctions; particle size; semiconductor thin films; silicon; silicon compounds; InN-InNO-In2O3-In-SiO2-Si; annealing temperature; annealing time; buffer layers; desorption; frequency 1.6 MHz; frequency 70 GHz; growth temperature; human body sensing signal; humidity sensor; microwave transmission property; negative differential resistance effect; p-n nanostructure; particle size; peak current density; peak-to-valley current ratio; quantum effect; quantum resonant microwave performance; resistive cutoff frequency; resonant microwave property; response sensitivity; self-resonant frequency; temperature 400 degC; time 15 min; water molecular adsorption; Annealing; Buffer layers; Humidity; Indium; Sensors; Silicon; Indium; humidity; indium; microwave; resistance; resonant; sensor;
