'Product Blog'

High quality LaLuO3, ALD grown from Lanthanum and Lutetium amidinates, is an ideal gate dielectric to replace SiO2 in MOSFETs

Silicon-based metal oxide semiconductor field effect transistors (MOSFETs) have encountered many challenges as they are scaled down to sub-nanometer size such as high leakage current, power consumption and dielectric breakdown.  High-k dielectrics such as hafnium oxide have been investigated as replacements for SiO₂ in MOSFETs but future scalability is still limited by the formation of a lower-k interfacial layer.  HfO₂ readily crystallizes at temperatures as low as ~500^o C.¹ The preferred dielectrics are to be amorphous with high thermal stability, no grain boundaries and excellent electrical properties.  Lanthanum lutetium oxide (LaLuO₃) is one of the most attractive high-k candidates due to its high dielectric constant, large band gap and an amorphous phase stable up to 1,000^o C.²   

LaLuO₃ films have been successfully grown in a flow-type atomic layer deposition (ALD) reactor using La and Lu amidinate precursors with water vapor at 300-350^oC.^{2, 3, 4}  The oxide films were amorphous and free of interfacial layers with high dielectric constant, low leakage current density and very few bulk traps.  These films are scalable to effective oxide thickness (EOT) < 1nm.⁴ 

Strem Chemical now offers these La and Lu amidinate ALD precursors for growing oxide films:

These products are both ideal ALD precursors being water reactive, thermally stable and sufficiently volatile based upon their TGA analysis.⁵

References:

1. Appl. Phys. Lett., 2003, 82, 106.
2. Appl. Phys. Lett., 2011, 98, 172902.
3. Appl. Phys. Lett., 2010, 97, 012106.
4. Electrochem. Solid St., 2009,12 (4), G13-G15.
5. Proceedings of the AVS Atomic Layer Deposition Conference, 2007, 1-25.

Products mentioned in this blog and related materials:

57-1200: Tris(N,N'-di-i-propylformamidinato)lanthanum(III), (99.999+%-La) PURATREM La-FMD, CAS# 1034537-36-4

57-1500: Tris(N,N-di-i-propylpentylamidinato)lanthanum(III), 98% (99.999%-La) PURATREM

71-1050: Tris(N,N'-di-i-propylacetamidinato)lutetium(III), 99%

Metal Amidinates

High Purity Precursors for CVD/ALD