RELIABILITY STUDY ON BST CAPACITORS FOR GAAS MMIC

Reliability of BST (Ba0.7Sr0.3TiO3) capacitors made by using a MOD tec hnique was studied in terms of TDDB. DLTS analysis revealed peak-shift toward the lower-temperature side as the degradation goes further. Ob tained energy level of interfacial states at grain boundaries was 0.75 eV. We found the capture cross section of the level increases after th e bias-temperature stress. We also found that the larger grain size of BST film gives longer lifetime. These results suggest that the reliab ility is to be determined by the interface of grains.