Mechanisms of leakage currents and d.c. breakdown are reviewed for several high-dielectric films in prototype use for ULSI DRAMs, including barium strontium titanate, lead zirconate titanate, and proprietary materials, with special emphasis upon electrode interface phenomena. The early theory of Von Hippel is reviewed, and attention is paid to the modified boundary conditions to the thermal breakdown equation given below for the finite dimensions of capacitors in real ULSI DRAMs (EBis the breakdown field):