Investigation of breakdown behavior for AlGaN HEMTs

The ability to accurately determine the breakdown voltage of microwave transistors is critical to the design of high power microwave amplifiers. The optimal bias point and output impedance should be selected to ensure that the load line of the device during peak output power does not intersect the portion of the IV curve where the device breaks down. This paper presents a technique to determine a drain-source breakdown voltage measurement that is useful for the design of high power microwave amplifiers. This measurement has been performed on GaN HEMTs from several different domestic foundries. Using the results of this experiment, an optimal bias point that makes use of the entire load line while at the same time avoiding the destructive effects of breakdown, can be selected.