Reliability improvement of Al-gate power GaAs-MESFET

This paper reports on the reliability improvement of Al-gate power GaAs-MESFET (FET) formed by the photoresist liftoff process (PLP). Al electromigration (EM) tolerance improvement with a higher deposition rate and lower outgas photoresist, a gate breakdown voltage (BVgd) improvement with fine recess control for the channel layer, and the mean time to failure (MTTF) at the 1-dB gain compression point in high-temperature RF operating life tests (HTRF) are described. We observed the parameters of the median time to failure (MTF) with high-temperature forward-bias tests (HTFB), as well as BVgd, and the gate current. The contributions of these parameters to MTTF are estimated by using an RF gate current simulation. (C) 2000 Scripta Technica.