Ta-Si-N and Si3N4 Encapsulants for InP

Abstract

ABSTRACTThin films of sputtered, amorphous Ta36Si14N50 (a metallic conductor) and Si3N4 (an insulator) were evaluated as encapsulants for (100)-oriented InP substrates. Thicknesses of both films were approximately 100 nm. During a 15 min annealing in Ar, liberated phosphorus was gettered by a <Si>ISiO2ITa(100 nm) collector placed face-to-face on encapsulated or non-encapsulated InP. The stability of the InP with the encapsulant was characterized by backscattering spectrometry, scanning electron microscopy, and x-ray diffraction. As measured by 4He++ backscattering spectrometry, detectable amounts of phosphorus do not arise in the Ta collectors for the Ta-Si-N and Si3N4 encapsulation schemes until 650 and 700°C, respectively. Failure of the Ta36Si14N50 film is catastrophic at 700°C whereas the Si3N4 film degrades locally commencing at 600°C.