Electrically Active Interface Defects in the (100)Si/SiO{sub}x/HfO{sub}2/TiN System: Origin, Instabilities and Passivation

摘要

An analysis of the origin and passivation of interface states in (100)Si/SiO{sub}x/HfO{sub}2/TiN capacitor structures is presented. For high-k gate/metal gate capacitors which exhibit relatively high interface state densities (> 1×10{sup}11cm{sup}(-2)) the dominant interfacial defects are silicon dangling bond (P{sub}(bo)) centres. For (100)Si/SiO{sub}x/HfO{sub}2/TiN capacitors which experience no high temperature thermal budget following HfO{sub}2/TiN gate formation (T<600°C), the devices exhibit instabilities, where the interface state densities are modified during electrical measurements. The origin of this instability is studied. The response of the interface state density to rapid thermal annealing (30s) in N{sub}2 over the temperature range 600-900°C is presented. In addition, results are presented for interface state passivation in forming gas (0.5H{sub}2/0.95N{sub}2) from 350-550°C for (100)Si/SiO{sub}x/HfO{sub}2/TiN gate stacks with no post deposition annealing following TiN gate formation and for devices following a 900°C, 30s N{sub}2 RTA.