Design and manufacture of a microwave low-noise transistor having beam-leads

The design and fabrication technology of a bipolar microwave low-noise transistor with a beam-lead structure is described. The process which we present here has the following advantages: it is simple, it results in a satisfactory device reliability (Ti-Pt-Au metallizations and final passivation by a Si3N4layer), and it can be applied to the finest geometrical structures produced at the present time. The comparison between the results obtained for transistors in the beam-lead configuration and those obtained for packaged transistors clearly shows that microwave transistors can be fabricated with beam-leads with no degradation of the high-frequency performance. For a beam-lead interdigitated structure having four emitters 1.5 µm in width, the performance at 2 GHz was typically: dB dB dB.