A Power Law Model for Assessment of Hot Electron Reliability in GaAs MESFETs and AlGaAs/InGaAs pHEMTs
Val Kaper * , Peter Ersland
M/A-COM Engineering & Technology Group
100 Chelmsford Street; Lowell, MA 01851
(978) 656-2817; erslandp@tycoelectronics.com
Abstract
Hot electron reliability experiments were conducted on
four GaAs FET processes. Observed device degradation was similar to the results
reported by other authors (e.g. decrease of the open channel current, and a
rightward shift and compression of the transconductance curve). While the
degradation modes were the same for all four processes, the degradation rates
were not. These results have led us to propose that the existing figure of
merit model [1] should be extended to a power law model, thereby incorporating
the dependence of device degradation rate on the reverse gate-drain current
density. The power law model coefficients along with the breakdown voltage
provide complete information about susceptibility of a particular process to
the hot electron induced degradation, and also indicate reliability limitations
on what type of dynamic load line and input power level can be safely used.