Improved InAlGaP-based heterostructure field-effect transistors

This investigation proposes the improved double δ-doped InGaP/InGaAs heterostructure field-effect transistor (HFET) grown by metalorganic chemical vapour deposition. The extrinsic transconductance (g_m) and saturation current density (I_max) of the double δ-doped InGaP/InGaAs HFET are superior to those of the previously reported single δ-doped InGaP/InGaAs HFETs. The first n-InAlGaP/GaAs HFET is also investigated because it has a high Schottky barrier, a large high band gap and a large conduction-band discontinuity (ΔE_C). Even without indium in the channel of the InAlGaP/GaAs HFET, g_m and I_max are as high as 170 mS mm^-1 and 410 mA mm^-1, respectively. The g _m values of these two HFETs remain large even when the gate voltages are positive. Moreover, the breakdown voltages of the two examined HFETs both exceed 40 V.