GaAs metal-semiconductor field-effect transistor with extremely low resistance nonalloyed ohmic contacts using an InAs/GaAs superlattice

GaAs metal-semiconductor field-effect transistors (MESFETs) with extremely low resistance nonalloyed ohmic contacts have been demonstrated. The contact structure consists of an n⁺-InAs/GaAs strained-layer superlattice and an InAs cap layer. Contact resistances as low as 0.036 Ω mm have been measured. These results represent the smallest figures reported to date for GaAs field-effect transistors. Nonalloyed MESFETs with 1 μm gate lengths had transconductances of about 210 mS/mm.