MONOLITHIC MICROWAVE INTEGRATED CIRCUITS HAVING BOTH ENHANCEMENT-MODE AND DEPLETION MODE TRANSISTORS

摘要

A gallium nitride based monolithic microwave integrated circuit includes a substrate (110), a channel layer (130) on the substrate and a barrier layer (140) on the channel layer. A recess (412) is provided in a top surface of the barrier layer. First gate, source and drain electrodes are provided on the barrier layer opposite the channel layer, with a bottom surface of the first gate electrode (210, 310) in direct contact with the barrier layer. Second gate (410), source (420) and drain (430) electrodes are also provided on the barrier layer opposite the channel layer. A gate insulating layer (412) is provided in the recess in the barrier layer, and the second gate electrode is on the gate insulating layer opposite the barrier layer and extending into the recess. The first gate, source and drain electrodes comprise the electrodes of a depletion mode transistor (200, 300), and the second gate, source and drain electrodes comprise the electrodes of an enhancement mode transistor (400).