Systematic Study of the Effect of La2O3 Incorporation on the Flatband Voltage and Si Band Bending in the TiN/HfO2 /SiO2 /p-Si Stack
Recent studies have shown that La{sub 2}O{sub 3} films can be used to adjust the threshold voltage (V{sub t}) of NMOS Hf-based high-k/metal gate devices to desirable values, and a dipole at the high-k/SiO{sub 2} interface has been proposed to explain the V{sub t} shifts. In order to investigate the mechanism of the V{sub t} shift further, we have measured the flatband voltage (V{sub fb}) and Si band bending of technologically relevant TiN/HfO{sub 2}/La{sub 2}O{sub 3}/SiO{sub 2}/p-Si stacks where the thickness and position of the La{sub 2}O{sub 3} layer have been systematically varied. We observed systematic changes in V{sub fb}, Si band bending and the HfO{sub 2}-Si valence band offset as a function of La{sub 2}O{sub 3} layer thickness and position. These changes can be explained by a band alignment model that includes a dipole at the high-k/SiO{sub 2} interface, thus supporting the work of previous authors. In addition, we have derived the theoretical relationship between V{sub fb} and Si band bending, which agrees well with our experimental measurements.
- Research Organization:
- BROOKHAVEN NATIONAL LABORATORY (BNL)
- Sponsoring Organization:
- USDOE SC OFFICE OF SCIENCE (SC)
- DOE Contract Number:
- AC02-98CH10886
- OSTI ID:
- 1041852
- Report Number(s):
- BNL--97530-2012-JA
- Journal Information:
- Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 11 Vol. 108; ISSN JAPIAU; ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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