Leakage Reduction and gm Enhancement in GaN HEMT for Enhanced Sensitivity in Fibrinogen Detection from Human Plasma

Device ON current, transconductance (g
_m
) and low leakage are the sensing performance parameters of interest when AlGaN/GaN HEMT is fabricated for application in the sensing domain bio-sensing applications. This paper presents the leakage reduction and g
_m
and ON current enhancement in an AlGaN/AlN/GaN MOS-HEMT (Metal Oxide Semiconductor Field Effect Transistor) with introduction of 10nm ALD (Atomic Layer Deposition) Al
₂
O
₃
as gate dielectric. DC characteristics of the device in terms of ON current, OFF current and sensing characteristics which depends on device g
_m
are seen to be improved with the incorporation of a 2nm GaN cap layer and a 1nm AlN spacer layer. The fabricated MOSHEMT device shows a high g
_m
of 110mS/mm with reduced leakage in nano ampere ranges. The MOS-HEMT device fabricated has been tested for fibrinogen detection and the device showcased a very high sensitivity of 0.108mA/gl
^-1
.