Humidity Effect on Chip Capacitors With Al2O3Multistage Anodised Films

In this paper the properties of capacitors with porous-barrier and barrier-type Al2O3 layers underhumidity tests are described and compared. The capacitance, conductance and dissipation factor ofthese 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 scaleare linear with the slope from 0.026 to 8.19. For capacitors with the porous-barrier type layer the slopeswere below unity in the whole humidity range while for capacitors with the barrier-type layer this wasonly true in the low humidity range (below 60% RH). The moisture effect on capacitors with solderbump and NiCr electrodes was extremely small. On the other hand the presence of chromium lyingdirect on Al2O3 film caused a rise in humidity sensitivity. The new ingenious technique of Al2O3 dielectriclayer preparation proposed affords the possibilities of producing capacitors with very low sensitivity tomoisture in both the low-and high-humidity ranges