GaAs FET High Power Pulse Reliability

Three types of commercially available GaAs FETs were studied under high power gate pulses to simulate the radar environment of transceivers which share the same antenna. Both single pulses and pulse trains of 10 ns and 1 μs pulse widths were used to gain an understanding of the physics of failure in these devices. Gradual degradation of the DC and RE characteristics was observed allowing study of the failure mechanisms before massive damage could occur to the channel region. Failures occurred primarily by electromigration from sharp points and other irregularities along the gate. Electromigration can be reduced by using gate and ohmic contact metallizations without sharp protrusions. These sharp protrusions and the resulting high fields lead to increased electromigration, particularly when the gate-source distance is very small.