Comparative electron spin resonance study of epi-Lu{sub 2}O{sub 3}/(111)Si and a-Lu{sub 2}O{sub 3}/(100)Si interfaces: Misfit point defects

Journal Article · Sat May 15 00:00:00 EDT 2010 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3326516· OSTI ID:21476195

Somers, P; Stesmans, A; Afanas'ev, V V ^[1]; Tian, W; Edge, L F; Schlom, D G ^[2]

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1. Department of Physics and Astronomy, University of Leuven, Celestijnenlaan 200D, 3001 Leuven (Belgium) and INPAC-Institute for Nanoscale Physics and Chemistry, University of Leuven, Celestijnenlaan, 200D Leuven (Belgium)
2. Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853-1501 (United States)

An electron spin resonance study has been carried out on heteroepitaxial Si/insulator structures obtained through growth of epi-Lu{sub 2}O{sub 3} films on (111)Si ({approx}4.5% mismatch) by molecular-beam epitaxy, with special attention to the inherent quality as well as the thermal stability of interfaces, monitored through occurring paramagnetic point defects. This indicates the presence, in the as-grown state, of P{sub b} defects ({approx}5x10{sup 11} cm{sup -2}) with the unpaired sp{sup 3} Si dangling bond along the [111] interface normal, the archetypical defect (trap) of the standard thermal (111)Si/SiO{sub 2} interface, directly revealing, and identified as the result of, imperfect epitaxy. The occurrence of P{sub b} defects, a major system of electrically detrimental interface traps, is ascribed to lattice mismatch with related introduction of misfit dislocations. This interface nature appears to persist for annealing in vacuum up to a temperature T{sub an{approx}}420 deg. C. Yet, in the range T{sub an{approx}}420-550 deg. C, the interface starts to ''degrade'' to standard Si/SiO{sub 2} properties, as indicated by the gradually increasing P{sub b} density and attendant appearance of the EX center, an SiO{sub 2}-associated defect. At T{sub an{approx}}700 deg. C, [P{sub b}] has increased to about 1.3 times the value for standard thermal (111)Si/SiO{sub 2}, to remain constant up to T{sub an{approx}}1000 deg. C, indicative of an unaltered interface structure. Annealing at T{sub an}>1000 deg. C results in disintegration altogether of the Si/SiO{sub 2}-type interface. Passivation anneal in H{sub 2} (405 deg. C) alarmingly fails to deactivate the P{sub b} system to the device grade (sub) 10{sup 10} cm{sup -2} eV{sup -1} level, which would disfavor c-Lu{sub 2}O{sub 3} as a suitable future high-{kappa} replacement for the a-SiO{sub 2} gate dielectric. Comparison of the thermal stability of the c-Lu{sub 2}O{sub 3}/(111)Si interface with that of molecular-beam deposited amorphous-Lu{sub 2}O{sub 3}/(100)Si shows the former to be superior, yet unlikely to meet technological thermal budget requirements. No Lu{sub 2}O{sub 3}-specific point defects could be observed.

• OSTI ID: 21476195
• Journal Information: Journal of Applied Physics, Vol. 107, Issue 9; Other Information: DOI: 10.1063/1.3326516; (c) 2010 American Institute of Physics; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANNEALING
COMPARATIVE EVALUATIONS
DIELECTRIC MATERIALS
DISLOCATIONS
ELECTRON SPIN RESONANCE
INTERFACES
LAYERS
LUTETIUM OXIDES
MOLECULAR BEAM EPITAXY
MOLECULAR BEAMS
PARAMAGNETISM
PASSIVATION
POINT DEFECTS
SILICON
SILICON OXIDES
TRAPS
BEAMS
CHALCOGENIDES
CRYSTAL DEFECTS
CRYSTAL GROWTH METHODS
CRYSTAL STRUCTURE
ELEMENTS
EPITAXY
EVALUATION
HEAT TREATMENTS
LINE DEFECTS
LUTETIUM COMPOUNDS
MAGNETIC RESONANCE
MAGNETISM
MATERIALS
OXIDES
OXYGEN COMPOUNDS
RARE EARTH COMPOUNDS
RESONANCE
SEMIMETALS
SILICON COMPOUNDS