Back to Search Start Over

Systematic study of the effect of La2O3 incorporation on the flatband voltage and Si band bending in the TiN/HfO2/SiO2/p-Si stack

Authors :
Alain C. Diebold
Robert D. Clark
Ming Di
Gert J. Leusink
Steven Consiglio
Eric Bersch
Source :
Journal of Applied Physics. 108:114107
Publication Year :
2010
Publisher :
AIP Publishing, 2010.

Abstract

Recent studies have shown that La2O3 films can be used to adjust the threshold voltage (Vt) of NMOS Hf-based high-k/metal gate devices to desirable values, and a dipole at the high-k/SiO2 interface has been proposed to explain the Vt shifts. In order to investigate the mechanism of the Vt shift further, we have measured the flatband voltage (Vfb) and Si band bending of technologically relevant TiN/HfO2/La2O3/SiO2/p-Si stacks where the thickness and position of the La2O3 layer have been systematically varied. We observed systematic changes in Vfb, Si band bending and the HfO2-Si valence band offset as a function of La2O3 layer thickness and position. These changes can be explained by a band alignment model that includes a dipole at the high-k/SiO2 interface, thus supporting the work of previous authors. In addition, we have derived the theoretical relationship between Vfb and Si band bending, which agrees well with our experimental measurements.

Details

ISSN :
10897550 and 00218979
Volume :
108
Database :
OpenAIRE
Journal :
Journal of Applied Physics
Accession number :
edsair.doi...........986b63539a45c44fbc8fdcf6d46c35cd