ABSTRACT
Compound semiconductor devices suffer from specific failure mechanisms, which are related to their limited maturity. Only the GaAs MESFETs exhibit a stable technology and an assessed reliability. The metallizations employed in HEMTs already benefit from this assessment. However, HEMTs are affected by problems related to hot carriers and impact ionization, due to the high electric fields in the channel. The trapping of carriers and the generation of defects in the different layers are responsible for the observed instabilities. The stability of the base doping is the main reliability concern for HBTs. The Be out-diffoses from the base and causes the gain degradation. The C exhibits a lower diffusivity, but it is affected by the presence of H, which cause gain variations.
