4H-SiC RF bipolar junction transistors

In this paper, we report on 4H-SiC bipolar junction transistors with record Dc and small signal RF characteristics. We have demonstrated devices with a power dissipation density of 3 MW/cm/sup 2/ and operation up to 580/spl deg/C. RF devices were measured with an f/sub t//f/sub MAX/ of 4/1.8 GHz, which to our knowledge are the highest values published to date for any SiC BJT. We designed and fabricated RF device structures with a 3/spl mu/m by 100 /spl mu/m emitter stripe. The device's epitaxial layer structure is shown in fig. The device is fabricated by dry etching a double-mesa structure as described. The structure was subsequently passivated, followed by the deposition of the emitter/collector metal and the base metal. A second isolation layer and wiring metal then completed the device fabrication.