0.5 nm EOT low leakage ALD SrTiO3 on TiN MIM capacitors for DRAM applications

We demonstrate for the first time record low Leakage-EOT (3.5 times 10^-7 A/cm² at 1V, EOT=0.49 nm) MIM capacitors fabricated using a low temperature (250degC) ALD SrTiO₃ (STO) deposition process on ALD TiN bottom electrode. While most previous work on STO used deposition techniques not compatible with high aspect ratio DRAM applications, recent work on ALD STO showed promise on noble-like metal electrodes (Ru, Pt) [1,2]. In this work, a low temperature ALD process with alternative precursor set and carefully optimized deposition and processing conditions enables the use of low-cost, manufacturable-friendly TiN electrode MIMcaps for future DRAM nodes. Composition (Sr-rich) and process optimization allowed minimization of interfacial EOT penalties and leakage reduction by decreasing the density of leakier STO grains.