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Secondary ion mass spectrometry and resonant ionisation mass spectrometry studies of nickel contacts to silicon carbide. / Gareth David John

Swansea University Author: Gareth David John

Abstract

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) and resonant ionisation mass spectrometry (RIMS) have been used to perform depth profile analyses on nickel (Ni) contacts to silicon carbide (SiC) to understand the interfacial properties. In particular, as-deposited Schottky contacts and hig...

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Published: 2004
Institution: Swansea University
Degree level: Doctoral
Degree name: Ph.D
URI: https://cronfa.swan.ac.uk/Record/cronfa42495
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spelling 2018-08-02T16:24:29.4469945 v2 42495 2018-08-02 Secondary ion mass spectrometry and resonant ionisation mass spectrometry studies of nickel contacts to silicon carbide. 80db2d66460c093bf220e5b99db99c0d NULL Gareth David John Gareth David John true true 2018-08-02 Time-of-flight secondary ion mass spectrometry (TOF-SIMS) and resonant ionisation mass spectrometry (RIMS) have been used to perform depth profile analyses on nickel (Ni) contacts to silicon carbide (SiC) to understand the interfacial properties. In particular, as-deposited Schottky contacts and high temperature annealed Ohmic contacts have been characterised. Previous literature had indicated that the chemistry of the interface controlled the electrical properties of the contact. Using the TOF-SIMS system, depth profiles have been performed with the standard duoplasmatron ion source and a newly introduced liquid metal ion gun. Sputtering conditions have been optimised enabling detailed depth profiling of Schottky and Ohmic samples. The data from these samples have indicated a distinct difference between the two contact types. Schottky samples have been shown to have an abrupt interface with any interfacial reaction appearing to be confined to the intimate interface. This region had no significant affect on ion yield. Conversely, the Ohmic samples exhibited an extended Si composition well into the Ni contact layer. Moreover, the ion yield varied substantially throughout the contact layer indicating matrix changes were present as a result of annealing to 1000&C. RIMS studied the variation of Ni atoms sputtered into the Ni ground state (a3F4) and first excited state (a3D3) to determine variation in chemical bonding as a function of depth through the contact. Using a defocused ion beam passing through an aperture, detailed depth profiles were obtained by using two-colour, two-step resonant ionisation scheme. Again, a significant variation exists between the RIMS signals from Ohmic and Schottky samples. The ratio of the excited state to ground state for Ni showed measurable variations indicative of multiple Ni-silicide phases. Models for these interfaces are proposed and support other studies performed on this material system. The success of these techniques is reviewed together with suggestions for experimental development. E-Thesis Analytical chemistry. 31 12 2004 2004-12-31 COLLEGE NANME Physics COLLEGE CODE Swansea University Doctoral Ph.D 2018-08-02T16:24:29.4469945 2018-08-02T16:24:29.4469945 Faculty of Science and Engineering School of Biosciences, Geography and Physics - Physics Gareth David John NULL 1 0042495-02082018162459.pdf 10801725.pdf 2018-08-02T16:24:59.0100000 Output 18566263 application/pdf E-Thesis true 2018-08-02T16:24:59.0100000 false
title Secondary ion mass spectrometry and resonant ionisation mass spectrometry studies of nickel contacts to silicon carbide.
spellingShingle Secondary ion mass spectrometry and resonant ionisation mass spectrometry studies of nickel contacts to silicon carbide.
Gareth David John
title_short Secondary ion mass spectrometry and resonant ionisation mass spectrometry studies of nickel contacts to silicon carbide.
title_full Secondary ion mass spectrometry and resonant ionisation mass spectrometry studies of nickel contacts to silicon carbide.
title_fullStr Secondary ion mass spectrometry and resonant ionisation mass spectrometry studies of nickel contacts to silicon carbide.
title_full_unstemmed Secondary ion mass spectrometry and resonant ionisation mass spectrometry studies of nickel contacts to silicon carbide.
title_sort Secondary ion mass spectrometry and resonant ionisation mass spectrometry studies of nickel contacts to silicon carbide.
author_id_str_mv 80db2d66460c093bf220e5b99db99c0d
author_id_fullname_str_mv 80db2d66460c093bf220e5b99db99c0d_***_Gareth David John
author Gareth David John
author2 Gareth David John
format E-Thesis
publishDate 2004
institution Swansea University
college_str Faculty of Science and Engineering
hierarchytype
hierarchy_top_id facultyofscienceandengineering
hierarchy_top_title Faculty of Science and Engineering
hierarchy_parent_id facultyofscienceandengineering
hierarchy_parent_title Faculty of Science and Engineering
department_str School of Biosciences, Geography and Physics - Physics{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Biosciences, Geography and Physics - Physics
document_store_str 1
active_str 0
description Time-of-flight secondary ion mass spectrometry (TOF-SIMS) and resonant ionisation mass spectrometry (RIMS) have been used to perform depth profile analyses on nickel (Ni) contacts to silicon carbide (SiC) to understand the interfacial properties. In particular, as-deposited Schottky contacts and high temperature annealed Ohmic contacts have been characterised. Previous literature had indicated that the chemistry of the interface controlled the electrical properties of the contact. Using the TOF-SIMS system, depth profiles have been performed with the standard duoplasmatron ion source and a newly introduced liquid metal ion gun. Sputtering conditions have been optimised enabling detailed depth profiling of Schottky and Ohmic samples. The data from these samples have indicated a distinct difference between the two contact types. Schottky samples have been shown to have an abrupt interface with any interfacial reaction appearing to be confined to the intimate interface. This region had no significant affect on ion yield. Conversely, the Ohmic samples exhibited an extended Si composition well into the Ni contact layer. Moreover, the ion yield varied substantially throughout the contact layer indicating matrix changes were present as a result of annealing to 1000&C. RIMS studied the variation of Ni atoms sputtered into the Ni ground state (a3F4) and first excited state (a3D3) to determine variation in chemical bonding as a function of depth through the contact. Using a defocused ion beam passing through an aperture, detailed depth profiles were obtained by using two-colour, two-step resonant ionisation scheme. Again, a significant variation exists between the RIMS signals from Ohmic and Schottky samples. The ratio of the excited state to ground state for Ni showed measurable variations indicative of multiple Ni-silicide phases. Models for these interfaces are proposed and support other studies performed on this material system. The success of these techniques is reviewed together with suggestions for experimental development.
published_date 2004-12-31T03:53:04Z
_version_ 1763752631292919808
score 11.013799

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