Růst měděných ostrůvku na SiO2 na zvýšených teplot.

Formation of copper islands on a native SiO2 surface at elevated temperatures

journal article - other

en

A combination of in situ X-ray photoelectron spectroscopy analysis and ex situ scanning electron- and atomic force microscopy has been used to study the formation of copper islands upon Cu deposition at elevated temperatures as a basis for the guided growth of copper islands. Two different temperature regions have been found: (I) up to 250 C only close packed islands are formed due to low diffusion length of copper atoms on the surface. The SiO2 film acts as a barrier protecting the silicon substrate from diffusion of Cu atoms from oxide surface. (II) The deposition at temperatures above 300 C leads to the formation of separate islands which are (primarily at higher temperatures) crystalline. At these temperatures, copper atoms diffuse through the SiO2 layer. However, they are not entirely dissolved in the bulk but a fraction of them forms a Cu rich layer in the vicinity of SiO2/Si interface. The high copper concentration in this layer lowers the concentration gradient between the surface and the substrate and, consequently, inhibits the diffusion of Cu atoms into the substrate. Hence, the Cu islands remain on the surface even at temperatures as high as 450 C.

Růst ostrůvků při depozici mědi na substrátu SiO2/Si za zvýšených teplot byl studován pomocí in-situ fotoelektronové spektroskopie (XPS) a ex-situ rastrovací elektronové mikroskopie (SEM) a mikroskopie atomárních sil (AFM). Byly nalezeny a popsány dvě teplotní oblasti: (I) Do teploty 250 C je substrát pokryt malými těsně uspořádanými ostrůvky; vrstva SiO2 představuje účinnou difúzní bariéru. (II) Depozice při teplotách nad 300 C vede ke tvorbě jednotlivých monokrystalických ostrůvků; při těchto teplotách dochází k difúzi mědi skrze vrstvu SiO2. Na rozhraní Si/SiO2 vzniká vrstva bohatá na měď, která snižuje koncetrační gradient mezi povrchem a substrátem a výrazně snižuje rychlost další difúze mědi do substrátu. Monokrystalické ostrůvky mědi tak zůstávají na povrchu až do teplot 450 C.

A combination of in situ X-ray photoelectron spectroscopy analysis and ex situ scanning electron- and atomic force microscopy has been used to study the formation of copper islands upon Cu deposition at elevated temperatures as a basis for the guided growth of copper islands. Two different temperature regions have been found: (I) up to 250 C only close packed islands are formed due to low diffusion length of copper atoms on the surface. The SiO2 film acts as a barrier protecting the silicon substrate from diffusion of Cu atoms from oxide surface. (II) The deposition at temperatures above 300 C leads to the formation of separate islands which are (primarily at higher temperatures) crystalline. At these temperatures, copper atoms diffuse through the SiO2 layer. However, they are not entirely dissolved in the bulk but a fraction of them forms a Cu rich layer in the vicinity of SiO2/Si interface. The high copper concentration in this layer lowers the concentration gradient between the surface and the substrate and, consequently, inhibits the diffusion of Cu atoms into the substrate. Hence, the Cu islands remain on the surface even at temperatures as high as 450 C.

Měď (Cu); Křemík (Si); Oxid křemičitý (SiO2); Fotoelektronová spektroskopie (XPS); Rastrovací elektronová mikroskopie (SEM); Difúze, Povrchové struktury.

Copper (Cu); Silicon (Si); Silicon dioxide (SiO2); Photoelectron spectroscopy (XPS); Scanning electron microscopy (SEM); Diffusion; Surface structures

2010

15.03.2010

0169-4332

256

11

3636–3641

6