Biased life tests and thermal storage at different temperatures have been performed on 2 W GaAs MESFETs from two different suppliers. Failure modes and mechanisms are correlated to device technology and are thermally activated. In samples with Au/Pd/Ti gate metallization we observed a decrease of Idss current and an increase of the gate diode reverse current. The former is related to the gate-semiconductor interaction, whereas annealing of GaAs surface states is responsible for the latter, which can cause the device burn-out. These degradations exhibit activation energies of 1 eV and 1.5 eV, respectively. In samples with Al gate metallization, we measured an increase of parasitic resistances possibly deriving from a degradation of the ohmic contacts.
Degradation mechanisms in 2 W MESFETs
PACCAGNELLA, ALESSANDRO;ZANONI, ENRICO
1991
Abstract
Biased life tests and thermal storage at different temperatures have been performed on 2 W GaAs MESFETs from two different suppliers. Failure modes and mechanisms are correlated to device technology and are thermally activated. In samples with Au/Pd/Ti gate metallization we observed a decrease of Idss current and an increase of the gate diode reverse current. The former is related to the gate-semiconductor interaction, whereas annealing of GaAs surface states is responsible for the latter, which can cause the device burn-out. These degradations exhibit activation energies of 1 eV and 1.5 eV, respectively. In samples with Al gate metallization, we measured an increase of parasitic resistances possibly deriving from a degradation of the ohmic contacts.
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