Design and Analytical Assessment of Non-Ideal Ion-Sensitive β-MIS-(AlGa)2O3/Ga2O3 High Electron Mobility Transistor

In this work, for the first time, we have investigated an analytical model for β-MIS-(AlGa)
₂
O
₃
/Ga
₂
O
₃
ion-sensitive FET by using commercial Silvaco and MATLAB tools for non-ideality behavior around the isoelectric point. Gouy-Chapman-Stern theory is used to analyze the electrical double layer with the electrolyte. Al
₂
O
₃
is used as a dielectric between (AlGa)
₂
O
₃
and electrolyte. The pH sensor detects the variation in hydrogen ion concentration in the aqueous solution. Different electrolyte concentrations (1 mM, 0.01 M, 0.1 M) are used in aqueous solution to find sensitive parameters such as surface potential, charge density, Alpha, β
_int
, C
_diff
and C
_DL
for different pH values. Changes in surface potential and other sensitive parameters affect the intensity of 2DEG at the interface of (AlGa)
₂
O
₃
and Ga
₂
O
₃
in β-MIS-(AlGa)
₂
O
₃
/Ga
₂
O
₃
HEMT. The behavior of pH- sensitive parameters are also discussed before and after the isoelectric point. Variation in electrolyte concentration shows that lower electrolyte concentration has high sensitivity. Effects of variation of pH on potential, H
⁺
and OH
⁻
concentration with bulk distance have also been discussed. Transfer characteristics, threshold voltage, I
_ON
/I
_OFF
of β-MIS-(AlGa)
₂
O
₃
/Ga
₂
O
₃
HEMT have been investigated for different pH values. Threshold voltage increases with pH when pH moves from acidic to basic medium.