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Edmonds M, Sardashti K, Wolf S, Chagarov E, Clemons M, Kent T, Park JH, Tang K, McIntyre PC, Yoshida N, Dong L, Holmes R, Alvarez D, Kummel AC. Low temperature thermal ALD of a SiN x interfacial diffusion barrier and interface passivation layer on Si xGe 1- x(001) and Si xGe 1- x(110). J Chem Phys 2017; 146:052820. [PMID: 28178835 DOI: 10.1063/1.4975081] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Atomic layer deposition of a silicon rich SiNx layer on Si0.7Ge0.3(001), Si0.5Ge0.5(001), and Si0.5Ge0.5(110) surfaces has been achieved by sequential pulsing of Si2Cl6 and N2H4 precursors at a substrate temperature of 285 °C. XPS spectra show a higher binding energy shoulder peak on Si 2p indicative of SiOxNyClz bonding while Ge 2p and Ge 3d peaks show only a small amount of higher binding energy components consistent with only interfacial bonds, indicating the growth of SiOxNy on the SiGe surface with negligible subsurface reactions. Scanning tunneling spectroscopy measurements confirm that the SiNx interfacial layer forms an electrically passive surface on p-type Si0.70Ge0.30(001), Si0.50Ge0.50(110), and Si0.50Ge0.50(001) substrates as the surface Fermi level is unpinned and the electronic structure is free of states in the band gap. DFT calculations show that a Si rich a-SiO0.4N0,4 interlayer can produce lower interfacial defect density than stoichiometric a-SiO0.8N0.8, substoichiometric a-Si3N2, or stoichiometric a-Si3N4 interlayers by minimizing strain and bond breaking in the SiGe by the interlayer. Metal-oxide-semiconductor capacitors devices were fabricated on p-type Si0.7Ge0.3(001) and Si0.5Ge0.5(001) substrates with and without the insertion of an ALD SiOxNy interfacial layer, and the SiOxNy layer resulted in a decrease in interface state density near midgap with a comparable Cmax value.
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Affiliation(s)
- Mary Edmonds
- Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093, USA
| | - Kasra Sardashti
- Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093, USA
| | - Steven Wolf
- Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093, USA
| | - Evgueni Chagarov
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA
| | - Max Clemons
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093, USA
| | - Tyler Kent
- Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093, USA
| | - Jun Hong Park
- Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093, USA
| | - Kechao Tang
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA
| | - Paul C McIntyre
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA
| | | | - Lin Dong
- Applied Materials, Sunnyvale, California 94085, USA
| | | | | | - Andrew C Kummel
- Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093, USA
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Chagarov E, Sardashti K, Kaufman-Osborn T, Madisetti S, Oktyabrsky S, Sahu B, Kummel A. Density-Functional Theory Molecular Dynamics Simulations and Experimental Characterization of a-Al₂O₃/SiGe Interfaces. ACS APPLIED MATERIALS & INTERFACES 2015; 7:26275-26283. [PMID: 26575590 DOI: 10.1021/acsami.5b08727] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Density-functional theory molecular dynamics simulations were employed to investigate direct interfaces between a-Al2O3 and Si0.50Ge0.50 with Si- and Ge-terminations. The simulated stacks revealed mixed interfacial bonding. While Si-O and Ge-O bonds are unlikely to be problematic, bonding between Al and Si or Ge could result in metallic bond formation; however, the internal bonds of a-Al2O3 are sufficiently strong to allow just weak Al bonding to the SiGe surface thereby preventing formation of metallic-like states but leave dangling bonds. The oxide/SiGe band gaps were unpinned and close to the SiGe bulk band gap. The interfaces had SiGe dangling bonds, but they were sufficiently filled that they did not produce midgap states. Capacitance-voltage (C-V) spectroscopy and angle-resolved X-ray photoelectron spectroscopy experimentally confirmed formation of interfaces with low interface trap density via direct bonding between a-Al2O3 and SiGe.
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Affiliation(s)
- Evgueni Chagarov
- Department of Chemistry and Biochemistry, University of California, San Diego , La Jolla, California 92093, United States
| | - Kasra Sardashti
- Department of Chemistry and Biochemistry, University of California, San Diego , La Jolla, California 92093, United States
| | | | | | - Serge Oktyabrsky
- Department of Nanoscale Science and Engineering, University at Albany-State University of New York , Albany, New York 12222, United States
| | - Bhagawan Sahu
- GlobalFoundries , Malta, New York 12020, United States
| | - Andrew Kummel
- Department of Chemistry and Biochemistry, University of California, San Diego , La Jolla, California 92093, United States
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Kerr AJ, Chagarov E, Gu S, Kaufman-Osborn T, Madisetti S, Wu J, Asbeck PM, Oktyabrsky S, Kummel AC. Preparation of gallium nitride surfaces for atomic layer deposition of aluminum oxide. J Chem Phys 2014; 141:104702. [DOI: 10.1063/1.4894541] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- A. J. Kerr
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093, USA
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA
| | - E. Chagarov
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA
| | - S. Gu
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093, USA
| | - T. Kaufman-Osborn
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA
| | - S. Madisetti
- Department of Nanoscale Science and Engineering, University at Albany–State University of New York, Albany, New York 12222, USA
| | - J. Wu
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093, USA
| | - P. M. Asbeck
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093, USA
| | - S. Oktyabrsky
- Department of Nanoscale Science and Engineering, University at Albany–State University of New York, Albany, New York 12222, USA
| | - A. C. Kummel
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA
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