Reliability Investigation of 1 Micron Depletion Mode IC MESFETs

A 1.6 eV activation energy has been observed for gate degradation of GaAs MESFETs fabricated with a commercially available 1 micron depletion mode IC process. Data from deep level transient spectroscopy (DLTS) and capacitance-voltage (C-V) measurements are consistent with a failure mechanism of gate metal interdiffusion into GaAs resulting in a decrease of channel thickness. The median life at 290 °C channel temperature (TCH) was 80 hours, with a lognormal sigma of 0.7. Using these values, the projected FET failure rate is less than 0.01%/l000 hours (100 FIT) during the first million hours of life at TCH= 150 °C.