Time dependent dielectric breakdown of paraelectric barium-strontium-titanate thin film capacitors for memory device applications

Barium-strontium-titanate (BST) is an important material for dynamic random access memory capacitor applications. In this work, BST thin films are pre pared by the sol-gel method and metal-BST-metal capacitors are fabricated. The time dependent dielectric breakdown (TDDB) of the BST capacitors is mea sured and analyzed. A new extrapolation method is developed to obtain the T DDB lifetime from the time to breakdown (t(BD)) data. The leakage current i s found to depend on the applied electric field in a power law relationship . The exponent in the power law relation is close to 1 in the low field reg ion (lower than 16 MV/m) and is about 16.5 in the high field region (larger than 16 MV/m). A correlation between the leakage current and the TDDB life time is established. The extrapolated lifetime is about 10(12) s at 3.3 V f or 330-nm-thick films. (C) 1998 American Institute of Physics. [S0021-8979( 98)08820-3].