Pseudoepitaxial transrotational structures in 14 nm-thick NiSi layers on [001] silicon.
In a system consisting of two different lattices, structural stability is ensured when an epitaxial relationship occurs between them and allows the system to retain the stress whilst avoiding the formation of a polycrystalline film. The phenomenon occurs if the film thickness does not exceed a critical value. Here we show that in spite of its orthorhombic structure, a 14 nm-thick NiSi layer can three-dimensionally adapt to the cubic Si lattice by forming transrotational domains. Each domain arises by the continuous bending of the NiSi lattice, maintaining a close relationship with the substrate structure. The presence of transrotational domains does not cause a roughening of the layer, but instead it improves the structural and electrical stability of the silicide in comparison with a 24 nm-thick layer formed using the same annealing process. These results have relevant implications for the thickness scaling of NiSi layers which are currently used as metallizations of electronic devices.
Alberti
Alessandra
A
CNR-IMM, Sezione di Catania, Stradale Primosole 50, 95121 Catania, Italy. alessandra.alberti@imm.cnr.it
Bongiorno
Corrado
C
Cafra
Brunella
B
Mannino
Giovanni
G
Rimini
Emanuele
E
Metzger
Till
T
Mocuta
Cristian
C
Kammler
Thorsten
T
Feudel
Thomas
T
D018360:Crystallography, X-Ray; D004581:Electronics; D046529:Microscopy, Electron, Transmission; D009532:Nickel / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry; D010825:Physics / Q000379:methods; D012825:Silicon / Q000737:chemistry*; D017655:Silicon Compounds / Q000737:chemistry*; D013696:Temperature
D017655:Silicon Compounds; C506609:nickel silicide; D009532:Nickel; D009584:Nitrogen; D012825:Silicon