Millimetre wave/microwave power combining from arrays of resonant tunnelling diodes defined by in-situ focused ion beam lithography

Single and planar arrays of embedded high current density resonant tunnelling diodes (RTDs) with a common emitter and collector electrical connection have been successfully fabricated. This was achieved through a novel technique combining in-situ Ga⁺ focused ion beam (FIB) lithography with molecular beam epitaxy (MBE) regrowth. In these devices, the tunnel current path is defined by and confined to regions intentionally left undamaged by the implantation. The ability to fabricate and contact an array of RTDs has a potential impact in realising millimetre wave/microwave power combining applications at terahertz frequencies. Room temperature DC and preliminary S-parameter results are presented here for individual and arrays of RTDs produced using this method