Fabrication and characterization of tensile In sub(0.3)Al sub(0.7)As barrier and compressive In sub(0.7)Ga sub(0.3)As channel pHEMTs having extremely low gate leakage for low-noise applications

This study focuses on the area of the epitaxial design, fabrication and characterization of a 1 mu m gate-length InP-based pseudomorphic high electron mobility transistor (pHEMT) using InGaAs-InAlAs material systems. The advanced epitaxial layer design incorporates a highly strained aluminum-rich Schottky contact barrier, an indium-rich channel and a double delta-doped structure, which significantly improves upon the conventional low-noise pHEMT which suffers from high gate current leakage and low breakdown voltage. The outstanding achievements of the new design approach are 99% less gate current leakage and a 73% increase in breakdown voltage, compared with the conventional design. Furthermore, no degradation in RF performance is observed in terms of the cut-off frequency in this new highly tensile strained design. The remarkable performance of this advanced pHEMT design facilitates the implementation of outstanding low-noise devices.