Fabrication of 200-GHz f/sub max/ resonant-tunneling diodes for integration circuit and microwave applications

Room-temperature current densities of 1.3*10/sup 5/ A/cm/sup 2/ and peak-to-valley ratios of 2.5 have been achieved for resonant tunneling diodes (RTDs) in the GaAs/AlAs material system. The devices were fabricated in a microwave-compatible process using topside contacts and a semi-insulating substrate to allow device integration. Proton implantation creates a nonconducting surface compatible with high-frequency coplanar transmission lines and other passive microwave structures.>