Reliability of Thin Film Nichrome Resistors Used on Radiation Hardened Integrated Circuits
Abstract
The effects of corrosion, oxidation and interdiffusion on the reliability of thin film Ni-Cr resistors were studied. These properties were found to depend upon the composition and thickness of the films. The Ni-Cr thin films were found to be corrosion-resistant to salt solutions and to most acids with the exception of HF solutions and now Ni-Cr etches. From 'water drop' tests it was found that unpassivated resistors are subject to anodic dissolution at potentials above 2.5V. The Al metallization also dissolves at potentials above 0.5V. Passivation with 10K angstrom of SiO2 protects the nichrome from anodic dissolution. The oxidation kinetics for 180 and 460 angstrom films show an initial rapid increase in resistance followed by a slower diffusion-limited process. By comparison, the resistance for 800 angstrom films remained nearly constant until after 8 hours at 500 C. The EBIC mode of the SEM revealed two phases in the films, so it was concluded that oxidation is a nonuniform process. Aluminum was observed to diffuse into the Ni-Cr resistors with an activation energy of 96 kcal/mole. No discontinuities in resistance were observed for times up to 24 hours at 500 C.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1973
- Accession Number
- AD0911401
Entities
People
- Wayne M. Paulson
Organizations
- Motorola Mobility