Enhanced Gate Swing in InP HEMTs With High Threshold Voltage by Means of InAlAsSb Barrier

We demonstrated the suitability of the InP HEMTs with the InAlAsSb Schottky barrier to realize the high threshold voltage (enhancement mode), low gate current, and low power consumption. This quaternary compound material increases the conduction band discontinuity to the InGaAs channel by introducing only 10% of antimony to InAlAs. The gate current is reduced by an order of the magnitude (or even more) at gate voltage range from 0.4 to 0.8 V. On the other hand, the large conduction band discontinuity causes larger parasitic source and drain resistance, which decreases the extrinsic transconductance. Nevertheless, the high-frequency performance is comparable to the device with the conventional InAlAs barrier layer. Therefore, the InAlAsSb barrier is a promising option for logic applications, which requires reduced gate current. FETs, gate current, high-electron mobility transistors (HEMTs), high frequency.