Humidity Effect on Chip Capacitors With Al2O3 Multistage Anodised Films
In this paper the properties of capacitors with porous-barrier and barrier-type Al2O3 layers under humidity tests are described and compared. The capacitance, conductance and dissipation factor of these structures were measured as a function of relative humidity ranging from 11% RH to 94% RH. It has been found that the dependences of electrical conductance on relative humidity on a log-log scale are linear with the slope from 0.026 to 8.19. For capacitors with the porous-barrier type layer the slopes were below unity in the whole humidity range while for capacitors with the barrier-type layer this was only true in the low humidity range (below 60% RH). The moisture effect on capacitors with solder bump and NiCr electrodes was extremely small. On the other hand the presence of chromium lying direct on Al2O3 film caused a rise in humidity sensitivity. The new ingenious technique of Al2O3 dielectric layer preparation proposed affords the possibilities of producing capacitors with very low sensitivity to moisture in both the low-and high-humidity ranges.
Copyright © 1992 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.