The scaling of electrical oxide thickness to 1.0 nm and below for advanced silicon devices requires a change from thermally grown oxides and nitrided oxides to deposited dielectrics which have dielectric constants, k, significantly greater than that of silicon dioxide, k0∼3.8. Implementation of the higher-k dielectrics into field effect transistor devices requires a processing protocol that provides separate and independent control over the properties of the Si-dielectric interface and the bulk dielectric film. Experiments to date have shown that plasma-grown nitrided oxides, ∼0.5-0.6 nm thick, satisfy this requirement. This paper addresses chemical bonding issues at the Si-dielectric interface and at the internal dielectric interface between the plasma-grown nitrided oxides and the high-k alternative dielectrics by applying constraint theory. Si-SiO2 is a prototypical interface between a "rigid" Si substrate and a "floppy" network dielectric, SiO2, and the interfacial properties are modified by a monolayer-scale transition region with excess suboxide bonding over what is required for an ideal interface. Additionally, the defect properties at the internal interface between a nitrided SiO2 interface layer and a bulk dielectric film reflect differences in the average number of bonds/atom, Nav, of the dielectrics on either side of that interface. Experimentally determined interfacial defect concentrations are shown to scale quadratically with increasing differences in Nav thereby establishing a fundamental basis for limitations on device performance and reliability.
|Original language||English (US)|
|Number of pages||8|
|Journal||Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures|
|State||Published - Dec 1 2000|
ASJC Scopus subject areas
- Condensed Matter Physics
- Electrical and Electronic Engineering