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Phase dependence of Schottky barrier heights for Ge–Sb–Te and related phase-change materials

Zhaofu Zhang, Yuzheng Guo Orcid Logo, John Robertson

Journal of Applied Physics, Volume: 127, Issue: 15, Start page: 155301

Swansea University Author: Yuzheng Guo Orcid Logo

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DOI (Published version): 10.1063/5.0001912

Abstract

The large difference of dielectric functions between the amorphous and crystalline phases of Ge–Sb–Te based phase-change materials (PCMs) used in memory storage devices also affects their Schottky barrier heights (SBHs) and thus their electrical device properties. Here, the SBHs of each phase of Ge2...

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Published in: Journal of Applied Physics
ISSN: 0021-8979 1089-7550
Published: AIP Publishing 2020
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URI: https://cronfa.swan.ac.uk/Record/cronfa54101
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first_indexed 2020-05-01T19:38:39Z
last_indexed 2020-06-04T19:09:27Z
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spelling 2020-06-04T17:47:20.8234528 v2 54101 2020-05-01 Phase dependence of Schottky barrier heights for Ge–Sb–Te and related phase-change materials 2c285ab01f88f7ecb25a3aacabee52ea 0000-0003-2656-0340 Yuzheng Guo Yuzheng Guo true false 2020-05-01 GENG The large difference of dielectric functions between the amorphous and crystalline phases of Ge–Sb–Te based phase-change materials (PCMs) used in memory storage devices also affects their Schottky barrier heights (SBHs) and thus their electrical device properties. Here, the SBHs of each phase of Ge2Sb2Te5, GeTe, GeSe, and SnTe are found by density functional supercell calculations. The Fermi level pinning factor S calculated for the crystalline phases (with a larger dielectric constant) is smaller than their amorphous phases, agreeing well with the empirical relationship linking SBH to a dielectric constant. The relatively large dielectric constant of crystalline PCMs arises from their resonant bonding (metavalent bonding), but their pinning factor is not always as small as empirically expected. The results are useful for optimizing the design of metal contacts for Ge–Sb–Te type phase-change memory devices. Journal Article Journal of Applied Physics 127 15 155301 AIP Publishing 0021-8979 1089-7550 21 4 2020 2020-04-21 10.1063/5.0001912 COLLEGE NANME General Engineering COLLEGE CODE GENG Swansea University 2020-06-04T17:47:20.8234528 2020-05-01T12:27:34.6966655 Zhaofu Zhang 1 Yuzheng Guo 0000-0003-2656-0340 2 John Robertson 3 54101__17169__16314e330fa741f6830bad7f741f9e04.pdf 54101.pdf 2020-05-01T13:39:44.1606892 Output 2970444 application/pdf Version of Record true 2021-04-15T00:00:00.0000000 true eng
title Phase dependence of Schottky barrier heights for Ge–Sb–Te and related phase-change materials
spellingShingle Phase dependence of Schottky barrier heights for Ge–Sb–Te and related phase-change materials
Yuzheng Guo
title_short Phase dependence of Schottky barrier heights for Ge–Sb–Te and related phase-change materials
title_full Phase dependence of Schottky barrier heights for Ge–Sb–Te and related phase-change materials
title_fullStr Phase dependence of Schottky barrier heights for Ge–Sb–Te and related phase-change materials
title_full_unstemmed Phase dependence of Schottky barrier heights for Ge–Sb–Te and related phase-change materials
title_sort Phase dependence of Schottky barrier heights for Ge–Sb–Te and related phase-change materials
author_id_str_mv 2c285ab01f88f7ecb25a3aacabee52ea
author_id_fullname_str_mv 2c285ab01f88f7ecb25a3aacabee52ea_***_Yuzheng Guo
author Yuzheng Guo
author2 Zhaofu Zhang
Yuzheng Guo
John Robertson
format Journal article
container_title Journal of Applied Physics
container_volume 127
container_issue 15
container_start_page 155301
publishDate 2020
institution Swansea University
issn 0021-8979
1089-7550
doi_str_mv 10.1063/5.0001912
publisher AIP Publishing
document_store_str 1
active_str 0
description The large difference of dielectric functions between the amorphous and crystalline phases of Ge–Sb–Te based phase-change materials (PCMs) used in memory storage devices also affects their Schottky barrier heights (SBHs) and thus their electrical device properties. Here, the SBHs of each phase of Ge2Sb2Te5, GeTe, GeSe, and SnTe are found by density functional supercell calculations. The Fermi level pinning factor S calculated for the crystalline phases (with a larger dielectric constant) is smaller than their amorphous phases, agreeing well with the empirical relationship linking SBH to a dielectric constant. The relatively large dielectric constant of crystalline PCMs arises from their resonant bonding (metavalent bonding), but their pinning factor is not always as small as empirically expected. The results are useful for optimizing the design of metal contacts for Ge–Sb–Te type phase-change memory devices.
published_date 2020-04-21T04:07:26Z
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score 11.036706

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