Effect of ions presence in the SiOCH inter metal dielectric structure

In this paper, the electrical instabilities of Inter Metal Dielectric (IMD) SiOCH are investigated. These instabilities concern leakage current between metal lines and dielectric breakdown. At room temperature IMD leakage current tends to increase with waiting time. At high temperature and without electrical stress, a defect recovering phenomenon occurs and leakage current decreases. Depending on the applied electrical field, different conduction mechanisms are activated. At low field, Ionic conduction predominates, whereas at high electric field, Poole-Frenkel conduction is predominant. Comparing data and simulation results, ion activation energy is estimated. Then, presence of alkaline ions in SiOCH is suggested as the cause of electrical instabilities. Finally, Time Dependent Dielectric Breakdown (TDDB) is modeled as a function of initial leakage current and stress voltage bias.