Initiation of a passivated interface between hafnium oxide and In(Ga)As(0 0 1)-(4x2)

Journal Article · Mon Jun 28 00:00:00 EDT 2010 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.3427584· OSTI ID:21559875

Clemens, Jonathon B; Bishop, Sarah R; Kummel, Andrew C ^[1]; Lee, Joon Sung ^[2]; Droopad, Ravi ^[3]

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1. Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Dr., 0358, La Jolla, California 92093-0358 (United States)
2. Department of Chemistry and Biochemistry/Materials Science and Engineering Program, University of California, San Diego, 9500 Gilman Dr., 0358, La Jolla, California 92093-0358 (United States)
3. Department of Physics, Texas State University-San Marcos, San Marcos, Texas 78666 (United States)

Hafnium oxide interfaces were studied on two related group III rich semiconductor surfaces, InAs(0 0 1)-(4x2) and In{sub 0.53}Ga{sub 0.47}As(0 0 1)-(4x2), via two different methods: reactive oxidation of deposited Hf metal and electron beam deposition of HfO{sub 2}. The interfaces were investigated with scanning tunneling microscopy and spectroscopy (STS). Single Hf atom chemisorption sites were identified that are resistant to oxidation by O{sub 2}, but Hf islands are reactive to O{sub 2}. After e{sup -} beam deposition of <<1 ML of HfO{sub 2}, single chemisorption sites were identified. At low coverage (<1 ML), the n-type and p-type HfO{sub 2}/InGaAs(0 0 1)-(4x2) interfaces show p-type character in STS, which is typical of clean InGaAs(0 0 1)-(4x2). After annealing below 200 deg. C, full coverage HfO{sub 2}/InGaAs(0 0 1)-(4x2) (1-3 ML) has the surface Fermi level shifted toward the conduction band minimum for n-type InGaAs, but near the valence band maximum for p-type InGaAs. This is consistent with the HfO{sub 2}/InGaAs(0 0 1)-(4x2) interface being at least partially unpinned, i.e., a low density of states in the band gap. The partially unpinned interface results from the modest strength of the bonding between HfO{sub 2} and InGaAs(0 0 1)-(4x2) that prevents substrate atom disruption. The fortuitous structure of HfO{sub 2} on InAs(0 0 1)-(4x2) and InGaAs(0 0 1)-(4x2) allows for the elimination of the partially filled dangling bonds on the surface, which are usually responsible for Fermi level pinning.

• OSTI ID: 21559875
• Journal Information: Journal of Chemical Physics, Vol. 132, Issue 24; Other Information: DOI: 10.1063/1.3427584; (c) 2010 American Institute of Physics; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ANNEALING
ATOMS
CHEMISORPTION
DEPOSITION
ELECTRON BEAMS
ELECTRONS
FERMI LEVEL
GALLIUM ARSENIDES
HAFNIUM OXIDES
INDIUM ARSENIDES
INTERFACES
OXIDATION
SCANNING TUNNELING MICROSCOPY
SEMICONDUCTOR MATERIALS
SPECTROSCOPY
SUBSTRATES
SURFACES
ARSENIC COMPOUNDS
ARSENIDES
BEAMS
CHALCOGENIDES
CHEMICAL REACTIONS
ELEMENTARY PARTICLES
ENERGY LEVELS
FERMIONS
GALLIUM COMPOUNDS
HAFNIUM COMPOUNDS
HEAT TREATMENTS
INDIUM COMPOUNDS
LEPTON BEAMS
LEPTONS
MATERIALS
MICROSCOPY
OXIDES
OXYGEN COMPOUNDS
PARTICLE BEAMS
PNICTIDES
REFRACTORY METAL COMPOUNDS
SEPARATION PROCESSES
SORPTION
TRANSITION ELEMENT COMPOUNDS