{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/18640"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/18640","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Transient phase change effect in phase change memory devices","abstract":"Phase change random access memory (PCRAM) is a leading contender for next generation nonvolatile memory. The phase change mechanism from high resistance amorphous phase to low resistance crystalline phase in nano-timescale is the most important characteristic of these materials. However, full understanding of the mechanism is still not achieved. Two time parameters were identified from the transient waveform, namely the delay and current recovery times. The link between crystallization kinetics and the transient phase change effect was established by associating nucleation with delay time and growth with current recovery time. Real-time crystallization characterization was achieved. Parasitic capacitance had strong implications on the programming performance of PCRAM. Larger parasitic capacitance results in a larger leakage current, and hence higher applied voltage for RESET operation needs to be applied. The larger parasitic capacitance also results in an increased quenching time due to a longer voltage fall time, which results in a partially crystallized amorphous state. Continuing work is studying the effect of filament formation on phase change. Filament formation is linked to the actual operating performance of the PCRAM device. This link is important in understanding how phase change occurs electrically and whether filament formation has any effect on scaling of PCRAM devices.","abstract_html":"Phase change random access memory (PCRAM) is a leading contender for next generation nonvolatile memory. The phase change mechanism from high resistance amorphous phase to low resistance crystalline phase in nano-timescale is the most important characteristic of these materials. However, full understanding of the mechanism is still not achieved. Two time parameters were identified from the transient waveform, namely the delay and current recovery times. The link between crystallization kinetics and the transient phase change effect was established by associating nucleation with delay time and growth with current recovery time. Real-time crystallization characterization was achieved. Parasitic capacitance had strong implications on the programming performance of PCRAM. Larger parasitic capacitance results in a larger leakage current, and hence higher applied voltage for RESET operation needs to be applied. The larger parasitic capacitance also results in an increased quenching time due to a longer voltage fall time, which results in a partially crystallized amorphous state. Continuing work is studying the effect of filament formation on phase change. Filament formation is linked to the actual operating performance of the PCRAM device. This link is important in understanding how phase change occurs electrically and whether filament formation has any effect on scaling of PCRAM devices.","abstract_has_math":false,"creators":["Yeo, Eng Guan"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Electrical & Computer Engr","degree_department":null,"school":null,"contributors":["Adesida, Ilesanmi","Jain, Kanti","Kim, Kyekyoon","Bishop, Stephen G."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-01-21T22:52:48Z","date_published":"2011-01-21T22:52:48Z","updated_at":"2026-07-22T22:25:11Z","subjects":["phase change memory","Phase change random access memory (PCRAM)","transient effect","time-resolved","filament"],"languages":["en"],"rights":["Copyright 2010 Eng Guan Yeo"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/18640","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Adesida, Ilesanmi","Jain, Kanti","Kim, Kyekyoon","Bishop, Stephen G."]},{"key":"dc:creator","label":"Author","values":["Yeo, Eng Guan"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-01-21T22:52:48Z","2013-01-22T11:00:18Z","2010-12"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Electrical & Computer Engr"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["phase change memory","Phase change random access memory (PCRAM)","transient effect","time-resolved","filament"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2010 Eng Guan Yeo"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/18640"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Phase change random access memory (PCRAM) is a leading contender for next generation nonvolatile memory. The phase change mechanism from high resistance amorphous phase to low resistance crystalline phase in nano-timescale is the most important characteristic of these materials. However, full understanding of the mechanism is still not achieved. Two time parameters were identified from the transient waveform, namely the delay and current recovery times. The link between crystallization kinetics and the transient phase change effect was established by associating nucleation with delay time and growth with current recovery time. Real-time crystallization characterization was achieved. Parasitic capacitance had strong implications on the programming performance of PCRAM. Larger parasitic capacitance results in a larger leakage current, and hence higher applied voltage for RESET operation needs to be applied. The larger parasitic capacitance also results in an increased quenching time due to a longer voltage fall time, which results in a partially crystallized amorphous state. Continuing work is studying the effect of filament formation on phase change. Filament formation is linked to the actual operating performance of the PCRAM device. This link is important in understanding how phase change occurs electrically and whether filament formation has any effect on scaling of PCRAM devices.","Item withdrawn by Mark Zulauf (zulauf@illinois.edu) on 2010-09-16T13:15:10Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 2 EngGuan_Yeo.docx: 7314436 bytes, checksum: 23ba4c6d5b1a3111238446273ae7dacc (MD5) EngGuan_Yeo.pdf: 3718717 bytes, checksum: 60b7abb009857659718bd38e02db868c (MD5)","Made available in DSpace on 2011-01-21T22:52:48Z (GMT). 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The phase change mechanism from high resistance amorphous phase to low resistance crystalline phase in nano-timescale is the most important characteristic of these materials. However, full understanding of the mechanism is still not achieved. Two time parameters were identified from the transient waveform, namely the delay and current recovery times. The link between crystallization kinetics and the transient phase change effect was established by associating nucleation with delay time and growth with current recovery time. Real-time crystallization characterization was achieved. Parasitic capacitance had strong implications on the programming performance of PCRAM. Larger parasitic capacitance results in a larger leakage current, and hence higher applied voltage for RESET operation needs to be applied. The larger parasitic capacitance also results in an increased quenching time due to a longer voltage fall time, which results in a partially crystallized amorphous state. 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