Hydrogen Sensing Characteristics of AlGaInP/InGaAs Complementary Co-Integrated Pseudomorphic Doping-Channel Field-Effect Transistors

摘要： In this article, the hydrogen sensing device and logic characteristics of the Al0.25Ga0.25In0.5P/In0.1Ga0.9As complementary co-integrated pseudomorphic doping-channel ?eld-effect transistors are demonstrated. Due to the existence of a relatively large conduction (valence) band discontinuity at Al0.25Ga0.25In0.5P/In0.1Ga0.9As heterojunction and the employment of a small energy-gap In0.1Ga0.9As channel layer, it could provide a high gate barrier height to avoid electrons (holes) injection form channel into gate region in the studied n-channel (p-channel) device. With respect to the n-channel (p-channel) transistor under hydrogen ambient, hydrogen molecules are adsorbed and dissociated on the Pd catalytic metal surface, followed by rapid diffusion of hydrogen atoms into the MS interface where the dipoles are formed to lower (elevate) the gate barrier height and enhance (decrease) the drain current. In the n-channel (p-channel) device, the threshold voltages at drain current of 0.1 mA/mm are of 0.67 (0.05) and 0.38 (?0.26) V in air and at hydrogen concentration of 9800 ppm, respectively. As hydrogen is detected, the characteristics of inverters shift left obviously, and the VOH and VIH values are decreased.