Selectively Regrown Contacts to Field-Effect Transistors with Two-Dimensional Electron-Gas Channels

We have fabricated for the first time heterostructure field-effect transistors where the two-dimensional electron gas (2-DEG) channel is directly contacted by selectively regrown epitaxial GaAs contacts. Both modulation-doped FET’s (MODFET’s) and semiconductor-insulator-semiconductor FET’s (SISFET’s) were fabricated. Contact resistances were low as evidenced by high transconductances and improvements to the transconductance at low temperatures. The low resistance and shallow nature of the regrown contacts should permit scaling of these structures to very small dimensions. © 1990 IEEE