Nonalloyed and in situ Ohmic contacts to highly doped n‐type GaAs layers grown by molecular beam epitaxy (MBE) for field‐effect transistors

摘要

MBE was used to grow n‐type GaAs layers doped with tin to approximately 5×1019 cm-3. Au/Ge Ohmic contacts were formed on the heavily doped layers without exceeding the eutectic temperature, thereby producing a nonalloyed Ohmic contact. In an in situ metallization experiment, tin was deposited on a freshly grown n++ layer. The deposited contact (without any heating) has linear current‐voltage characteristics. Power GaAs FET’s were fabricated with nonalloyed Au/Ge contacts which showed excellent rf and dc characteristics. The combination of MBE n++ layer growth and the technology presented here may have potential for microwave devices and GaAs integrated circuits.