Current AlGaN/GaN Heterojunction Field Effect Transistors (HFETs) make use of multiple sources, drains, and gates in parallel 
to maximize transconductance and effective gain while minimizing the current density through each channel. To connect the 
sources to a common ground, current practice prescribes the fabrication of air bridges above the gates and drains. This 
practice has the advantage of a low dielectric constant and low parasitic capacitance, but it is at the expense of 
manufacturability and robust device operation.<p>

In the study described below, the air bridges in AlGaN/GaN HFETs were replaced by a polymer supported metallization bridge 
with the intention of improving ease of fabrication and reliability. The DC, high frequency, and power performance for 
several polymer step heights were investigated. The resultant structures were functional and robust; however, their 
electrical performance was degraded due to high source resistance. The cause of the high source resistance was found to be 
thinning of the metallization at the polymer step. The effect was more pronounced for higher step heights.