Schadensanalyse des Dielektrikums - DP5704

According to some applications of hybrid circuits it can occur that corresponding the long term test of the reliability for a dielectric (85 degree, 85 RH, 1 000 h) is not sufficient Therefore the fired layers of DP 5704 and C 1214D were tested at 30 degree, 95 RH and different voltages (0...15 V) up to 30 days and interimly electrically characterized. The structure of the dielectric was analyzed at fracture surfaces with SEM and EDX This storage conditions lead to following effects The humidity does not penetrate through the planar electrode of the capacitor in the dielectric but about the opening edges only. The insulation resitivity (Riso) and the breakdown voltage decrease and tan delta increases with the time. In the case Riso smaller 10000000 Ohm and tan delta is unchanged small we often observed an increasing of the Riso at a later time. Generally the dielectrics showed at Riso smaller 10000000 Ohm a varistor like behavior. It is shown that the measuring results can be explained by the surface roughness of the dielectrics and by differences in the void distribution. The results suggest ideas for the improvement of the material properties.