Enhancement of pH-sensitivity using In_0.53Ga_0.47As channel ion-sensitive-field-effect-transistors

In this paper, for the first time, a pH-sensor using an In_0.53Ga_0.47As based ion-sensitive-field-effect-transistor (ISFET) is proposed to show its superior sensing performance as compared to its equivalent Si counterpart. Extensive numerical analyses of the proposed In_0.53Ga_0.47As-ISFET are performed in order to extract various sensitivity parameters, e.g., threshold voltage sensitivity (V_th-sensitivity), ON-current sensitivity (I_ON-sensitivity), and gate-voltage sensitivity (V_GS-sensitivity), followed by the performance comparison with the equivalent Si-ISFET sensor, the experimental data of which are used for calibration of the simulation framework. The obtained results show that the long-channel In_0.53Ga_0.47As-ISFET sensor exhibits 10, 962%, and 9.75% improvement for V_th-sensitivity, I_ON-sensitivity, and V_GS-sensitivity respectively, compared to the equivalent Si-ISFET-sensor at supply voltage of 0.5 V. Furthermore, our findings reveal that a down-scaled ISFET, for instance, a 40-nm-In_0.53Ga_0.47As-ISFET sensor shows 26, 213% and 10.5% improvement of V_th-sensitivity, I_ON-sensitivity, and V_GS-sensitivity, respectively at the same supply voltage compared to its equivalent Si ISFET sensor.