Advanced 200 nm gate profile fabrication with reactive ion etching

A processing sequence for the fabrication of Y-shaped profiles for HEMTs and MESFETs using electron beam lithography (EBL) and reactive ion etching (RIE) will be presented. On the top of a tri-layer resist system the gate line is defined by EBL and transferred to the substrate by RIE without expansion of lateral dimensions. The enlargement of the upper part of the profile is done by isotropic and anisotropic RIE steps and of the metallization will be discussed. First DC-characteristics of a MESFET with an etched Y-gate will be given.