The effects of film composition and postnitridation annealing on band gap and valence band offset were examined in nitrided Hf-silicate films prepared using direct plasma nitridation. Regardless of the composition of Hf-silicate films, the band gap characteristics were similar after direct plasma nitridation (4.5±0.1 eV) and postnitridation annealing (5.6±0.1 eV). The decrease in band gap after direct plasma nitridation was caused by the formation of Si-N and Hf-N bonds, while the recovery of band gap by postnitridation annealing was influenced by the dissociation of unstable Hf-N bonds. The difference in valence band offset was strongly related to the chemical states of Si-N bonds.
Bibliographical noteFunding Information:
This work was partially supported by the National Program for Tera-level Nanodevices of the Ministry of Science and Technology as one of the 21 Century Frontier Programs. This work was also supported by Korea Science and Engineering Foundation Grants (R01-2004-000-10882-0).
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)