Very high performance 0.15 mu m gate-length InAlAs/InGaAs/InP lattice-matched HEMTs

State-of-the-art high-electron-mobility-transistor (HEMT) devices have been fabricated on InAlAs/InGaAs/InP. Devices with 30- mu m and 50- mu m gate widths and 0.15- mu m gate length were fabricated using an all-electron-beam lithography process. After mesa formation, ohmic contacts were formed using a standard NiAuGe metallization. The contacts were annealed using a rapid thermal annealer. Typical ohmic contact resistance was approximately 0.13 Omega -mm. This is the same as the typical contact for the GaAs-based pseudomorphic HEMT result. Gates were defined using a trilayer resist scheme and recessed using a wet chemical etch to reach the desired channel current. A TiPtAu metallization forms the gate. The devices exhibited performance superior to most other low noise HEMT devices. It is found that the gate leakage current increases as recess depth increases. This current increase seems to degrade noise performance.<
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