The change of oxidation state of Si with the growth of HfO2 thin films on SiO2 and the effects on the electrical properties
Abstract
Of the many materials with high dielectric constants, phk, which have been studied to replace SiO2 as a gate dielectric for metal-oxide-semiconductor devices, hafnium oxide (HfO_2) is one of the most promising. We have studied the microscopic mechanism of initial growth and the electrical properties of the ultra thin films of HfO_2. HfO2 thin films were grown on SiO2 with thickness ranging from sub-monolayer to few nanometers by a custom build laser molecular beam epitaxy system. An phin-situ scanning tunneling microscopy and an x-ray photoelectron spectroscopy were used to analyze the films. We observed a change in the oxidation states of the Si with varying the thickness of HfO2 films on SiO2 and the oxygen pressure during the growth. The amount of Si^4+ decreased with increasing the thickness and decreasing the oxygen pressure, which implies the diffusion of oxygen from SiO2 to HfO_2. The effects of the change on the electrical properties of the film will be presented.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 2004
- Bibcode:
- 2004APS..MARW39006C