Measurement Technique of Carrier Mobility in Silicon Nitride and its Application to Data Retention in MONOS Memories

A novel method to measure carrier mobilities in insulators such as silicon nitride was developed. The transport parameters were determined by measuring the threshold voltage shift and the gate leakage current during the retention simultaneously. The electric field and the temperature dependence of the mobility in Si3N4 shows the trap barrier lowering proportional to the electric field (E) in contrast with the Poole-Frenkel emission theory, where the trap barrier reduction is proportional to Efrac12. Based on the measured parameters, data retention characteristics are predictable for different device structures with a single parameter set.