Current collapse, memory effect free GaN HEMT

Current collapse in GaN HEMT leads to bias condition induced memory effect, and gradual power saturation, which are particularly detrimental to broadband RF amplifiers operating with large peak-to-average signal level. A novel ohmic metal scheme presenting low energy barrier to both the polarization induced, transistor channel electrons, and the surface mobile holes, is found to be effective in eliminating the undesirable, time and signal strength dependent behavior of the transistor performance charactics. The new founding represents a major breakthrough in polar semiconductor device technology for microwave power amplification. In this paper, the root cause of current collase is also briefly described.