Effect of oval defects in GaAs on the reliability of SiN x metal–insulator–metal capacitors

Abstract

In this paper, we will assess the reliability of extrinsic defects in SiN x metal–insulator–metal (MIM) capacitors as part of a GaAs high voltage (HV) FET process. The epitaxial GaAs layers used for this process contain a density of oval defects. Since the SiN x is deposited at low temperatures, the MIM capacitors are amorphous and will always contain a certain amount of extrinsic defects. It will be shown that the number of extrinsic defects depends on the presence of the oval defects in the epitaxial GaAs layers. The reliability assessment will be done using electric field breakdown (Ebd), time dependent dielectric breakdown (TDDB) measurements and visual inspection. It will be shown that this combination can lead to an estimate of the lifetime and screening of capacitors containing extrinsic defects.