Ultrahigh speed high electron mobility transistor large scale integration technology

Current status and recent advances in high electron mobility transistor (HEMT) technology for high performance very large scale integration (VLSI) are presented with the focus on material, self‐alignment device fabrication, and HEMT large‐scale integration (LSI) implementations. HEMT is a very promising device for ultrahigh speed LSI/VLSI due to the supermobility GaAs/AlGaAs heterojunction structure. The technological challenges for large scale integrations are discussed with refined HEMT with self‐aligned gate structure, controllability of device parameters, and molecular beam epitaxy material problems. Master–slave flip–flop, divide‐by‐two circuits achieved the internal logic delay of 22 ps per gate at 77 K at a fan‐out of about 2, roughly three times faster than that of GaAs metal‐semiconductor field‐effect transistor technology. HEMT has already made it possible to develop 16 kb static random access memory (RAM) and a 1.5‐kgate gate array, demonstrating high speed LSI operations. With submicron gates,...