Authors: D. Mateos, A. Arias, N. Nedev, M. Curiel, V. Dzhurkov, E. Manolov, D. Nesheva, O. Contreras, B. Valdez, I. Bineva, O. Raymond, J.M. Siqueiros
Affilation: Autonomous University of Baja California, Mexico
Pages: 396 - 399
Keywords: Si nanocrystals, MOS, TEM, I-R, I-V, C-V, two step annealing
MOS structures with two and three-region gate dielectrics containing Si nanocrystals are prepared and characterized by TEM, IR spectroscopy and electrical measurements. c Si/SiO2 containing Si NCs/SiO2/Al structures were obtained by high temperature annealing of SiO1.15 films deposited on n-type Si first in pure N2 and then in 90% N2 + 10% O2 atmospheres. The three-region MOS structures (c-Si/SiO2/SiO2-Si NCs/SiO2/Al) were fabricated by thermal oxidation of n-cSi, followed by the steps described above. TEM results proved the formation of two regions in the SiO1.15 films: the first one, far from the top surface exhibits Si nanocrystals (~ 3-4 nm), while the second one close to the top surface shows a uniform amorphous SiO2 phase. IR measurements indicate phase separation and formation of nanocrystals in a SiO2 matrix as well as complete oxidation of the excess Si in the top region. I-V measurements on two-region MOS structures showed that the top SiO2 has high quality dielectric properties. C-V measurements revealed that the density of states at the c-Si/SiO2-Si NCs interface is high. In contrast the three-region MOS structures display excellent C-V as well as I-V characteristics.