Atomic Transport and Chemical Stability during Annealing of UltrathinAl2O3Films on Si

Abstract

Ultrathin films of Al2O3 deposited on Si were submitted to rapid thermal annealing in vacuum or in oxygen atmosphere, in the temperature range from 600 to 800 degrees C. Nuclear reaction profiling with subnanometric depth resolution evidenced mobility of O, Al, and Si species, and angle-resolved x-ray photoelectron spectroscopy revealed the formation of Si-Al-O compounds in near-surface regions, under oxidizing atmosphere at and above 700 degrees C. Under vacuum annealing all species remained essentially immobile. A model is presented based on diffusion-reaction equations capable of explaining the mobilities and reproducing the obtained profiles.

Thermal stability and diffusion in gadolinium silicate gate dielectric films

“…16 In the latter films, which were initially oxygen rich ͓͑O͔Ͼ3/2͓La͔ϩ2͓Si͔͒, further Si diffusion was observed after annealing at temperatures as low as 750°C. The diffusion of silicon from the substrate is not universally observed in aluminum oxide films 10 and may not occur in all zirconium or hafnium silicate films. 1 More experiments need to be performed to determine the factors determining Si diffusion in high-films, but the apparent tendency of gadolinium silicate films to have a slight oxygen deficiency, rather than a pronounced excess or deficiency, may be a significant advantage.…”

“…These processes can lead to the formation of silicon dioxide which can undergo subsequent reactions, which are not thermodynamically forbidden, with the metal oxide or silicate. 9,10 It is thus important to determine the extent to which oxygen and silicon are mobile in the insulator during high-temperature processing.…”

Post deposition annealing of aluminum oxide deposited by atomic layer deposition using tris(diethylamino)aluminum and water vapor on Si(100)

“…Silicate formation at the interface during 800°C annealing has been reported to be dependant on annealing ambience. Krug et al report silicate formation in O 2 ambience and no significant change at the interface when annealed under vacuum at 800°C [9].…”

Preparation of α-Al2O3 thin films by electron cyclotron resonance plasma-assisted pulsed laser deposition and heat annealing

“…12 There are also reports on the preparation of Al 2 O 3 films on Si substrates by MOCVD, atomic-layer chemical vapor deposition, and oxidation of aluminum films, and studies on the properties of the Al 2 O 3 / Si interface as well. [13][14][15][16] Katiyar et al deposited amorphous Al 2 O 3 thin films on Si ͑100͒ by pulsed laser deposition ͑PLD͒ using pure aluminum oxide target. 17 In the present work, we prepared ␣-Al 2 O 3 thin films on Si͑100͒ substrates by electron cyclotron resonance ͑ECR͒ plasma-assisted PLD ͑ECR-PLD͒ and postdeposition heat annealing.…”