BURIED-CHANNEL WNX W SELF-ALIGNED GAAS-MESFET PROCESS WITH SELECTIVELY IMPLANTED CHANNEL AND UNDOPED EPITAXIAL SURFACE-LAYERS FOR MMIC APPLICATIONS/

The combined process of epitaxy and ion implantation has been develope d in the fabrication of a buried-channel WNx/W self-aligned GaAs metal -semiconductor field-effect transistor (MESFET). This MESFET comprises an ion-implanted channel and an undoped GaAs epitaxial surface layer. The ion-implantation technique leads to an IC-oriented process and th e epitaxial technique to a buried channel structure. Both ease of isol ation and enhanced breakdown voltage were attained, promising monolith ic microwave integrated circuits (MMICs) for L-band digital mobile com munication systems.