NOVEL SUBMICRON FABRICATION TECHNIQUE.

The fabrication technique described uses conventional photolithography and selective edge plating, in which a metal line is plated to the edge of a conventionally patterned metal layer. The plated edge is then used as a mask for subsequent plasma etching of underlying conductors of dielectrics. This technique has produced linewidths as small as 0. 04 mu m and can be applied to the fabrication of a variety of microwave devices. In particular, it has been used to produce GaAs MESFETs with gold-plated chromium gates as short as 0. 1 mu m. The performance of GaAs MESFETs produced in this manner is comparable to that of devices fabricated using more complex and expensive gate patterning techniques. For example, MESFETs on ion-implanted GaAs with 5 mu m source-drain spacings, 0. 3 mu m gate lengths, and 250 mu m gate widths have exhibited maximum available gains of over 10 db at a frequency of 12 GHz.