Compatibility of High K Dielectrics with TiCl_4-based TiN for MIS Storage Capacitors for sub 70 nm DT DRAM Technology and beyond

摘要

The introduction of high K dielectrics in combination with metal electrodes in deep trench (DT) DRAM storage capacitors for technology beyond 70nm ground rule is mandatory. In this paper, we study the compatibility of TiCl_4-based TiN electrodes with two dielectric materials (Al203 and HfSiO_x). The impact of the applied thermal budget on the electrical properties and the role of residual chlorine in the electrode are investigated. Compatibility of the dielectrics with the TiN deposition process is also studied. For the Al_2O_3/TiN system, high temperatures and high chlorine concentration lead to degradation of capacitance and leakage current. HfSiO_x dielectric is less sensitive to the chlorine concentration in the electrode. Exposure of the dielectric to the TiCl_4 precursor leads to degradation of the electrical properties for the both high K materials.