3D Integration of GaAs MESFET and varactor diode for a VCO-MMIC

For the optimization of MESFET and varactor diode in a monolithic microwave integrated circuit (MMIC) different epitaxial layer structures are required. We report on the 3-d integration of the different devices by stacking the specific layers upon each other. DC and RF performances of the integrated FET are improved introducing an insulating layer sequence. A voltage controlled oscillator (VCO) has been realized with the first design for a frequency of oscillation of 9 GHz.