Ku- and K-band GaAs MMIC varactor-tuned FET oscillators using MeV ion-implanted buried-layer back contacts

An all ion-implant, planar process has been used to fabricate high-Q hyperabrupt carrier profile varactor diodes for use in GaAs monolithic microwave IC (MMIC) voltage-controlled oscillators (VCOs) with the state-of-the-art performance. These GaAs varactor-tuned FET oscillators operate at up to 24 GHz with a tuning bandwidth of 5 GHz in K-band. The high-Q varactors feature a buried N/sup +/ layer created by ion-implantation at up to 6 MeV. Separately masked implanted N/sup +/ areas connect the buried layer to ohmic contacts at the surface. A varactor f/sub c/ of 1600 GHz was obtained at 0.09 pF. The design, fabrication, and measurements of varactors and MMIC VCOs are described.<
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