A novel submicron fabrication technique

A novel technique for producing submicron linewidths and devices has been developed. The technique does not require electron beam or other exotic lithographic techniques, but instead uses conventional photolithography and a selective edge planing step. In this step, a metal is plated to the edge of a conventionally patterned metal layer. This plated edge is then used as a mask for subsequent plasma etching of underlying conductors or dielectrics. This technique has produced linewidths as small as 0.04 µm 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 µm. 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 µm source-drain spacings, 0.3 µm gate lengths, and 250 µm gate widths, have exhibited maximum available gains of over 10 dB at a frequency of 12 GHz.