Reliability and failure analysis of MMIC amplifier fabricated on various GaAs substrates

The results are presented of stress aging characteristics of an ion-implanted GaAs MMIC (monolithic microwave IC) IF amplifier fabricated on four different substrate materials: 3-in. undoped, chromium-doped, indium-doped, and highly polished, undoped GaAs LEC (liquid encapsulated Czochralski) substrates. Three long-term and six accelerated aging tests were performed on more than 900 amplifiers totaling 32000 hours. These tests indicate that primary factors affecting device lifetime are process variations, GaAs substrate material, and substrate surface polish. Good reliability is predicted for amplifiers fabricated on Cr-doped, undoped, and advanced polished substrate. In-doped samples show instability and inadequate reliability. The failure analysis indicates that the primary causes of device degradation are GaAs-metal interface electromigration, interdiffusion, and active carrier density compensation. >