The Impact of Gate Recess on the H₂ Detection Properties of Pt-AlGaN/GaN HEMT Sensors
Robert Sokolovskij (Southern University of Science and Technology , TU Delft - Electronic Components, Technology and Materials)
Jian Zhang (Fudan University)
Hongze Zheng (Ministry of Education, Shenzhen, GaN Device Engineering Technology Research Center of Guangdong, Southern University of Science and Technology , Shenzhen Institute of Wide-bandgap Semiconductors)
Wenmao Li (Ministry of Education, Shenzhen, GaN Device Engineering Technology Research Center of Guangdong, Shenzhen Institute of Wide-bandgap Semiconductors, Southern University of Science and Technology )
Yang Jiang (GaN Device Engineering Technology Research Center of Guangdong, Southern University of Science and Technology , Shenzhen Institute of Wide-bandgap Semiconductors, Ministry of Education, Shenzhen)
Gaiying Yang (Southern University of Science and Technology )
Hongyu Yu (GaN Device Engineering Technology Research Center of Guangdong, Shenzhen Institute of Wide-bandgap Semiconductors, Ministry of Education, Shenzhen, Southern University of Science and Technology )
Pasqualina M. Sarro (TU Delft - Electronic Components, Technology and Materials)
Guoqi Zhang (TU Delft - Electronic Components, Technology and Materials)
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Abstract
The present work reports on the hydrogen gas detection properties of Pt-AlGaN/GaN high electron mobility transistor (HEMT) sensors with recessed gate structure. Devices with gate recess depths from 5 to 15 nm were fabricated using a precision cyclic etching method, examined with AFM, STEM and EDS, and tested towards H2 response at high temperature. With increasing recess depth, the threshold voltage ( VTH ) shifted from -1.57 to 1.49 V. A shallow recess (5 nm) resulted in a 1.03 mA increase in signal variation ( Δ IDS ), while a deep recess (15 nm) resulted in the highest sensing response ( S ) of 145.8% towards 300 ppm H2 as compared to reference sensors without gate recess. Transient measurements demonstrated reversible H2 response for all tested devices. The response and recovery time towards 250 ppm gradually decreased from 7.3 to 2.5 min and from 29.2 to 8.85 min going from 0 nm to 15 nm recess depth. The power consumption of the sensors reduced with increasing recess depth from 146.6 to 2.95 mW.