Design and fabrication of modulation doped charge coupled devices for transversal filter applications

This paper presents the first reported quarter-micron double delta doped AlGaAs/InGaAs charge coupled device for microwave frequency filter applications. The design and fabrication of conventional and multi tapped delay line MMICs for RF filter applications are also discussed. The device is implemented as a recessed capacitive gate structure which is fabricated using established GaAs heterostructure MMIC technology to ensure good repeatability. In transistor mode, the three stage device behaved as a multi-gated pseudomorphic high electron mobility transistor with a drain-source saturation current of 32 mA and an off-state drain-gate breakdown voltage of 2.8 V.