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ITO‐coatings by reactive low‐voltage ion plating: film properties and plasma analysis
Author(s) -
Huber Daniel,
Pulker H.K
Publication year - 2009
Publication title -
vakuum in forschung und praxis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.213
H-Index - 13
eISSN - 1522-2454
pISSN - 0947-076X
DOI - 10.1002/vipr.200900379
Subject(s) - ion plating , materials science , plasma , coating , oxide , analytical chemistry (journal) , indium tin oxide , electrical resistivity and conductivity , ion , deposition (geology) , thin film , chemical engineering , nanotechnology , chemistry , metallurgy , organic chemistry , paleontology , physics , engineering , quantum mechanics , sediment , biology , electrical engineering
Transparent conductive oxides (TCO) are widely used materials for multifarious applications. According to today's state of knowledge, indium‐tin‐oxide (ITO) still offers the best electrical properties among numerous TCOs. However, ITO films produced by ion plating have only rarely been reported to be investigated. For most coating processes, ITO films need to be deposited under high temperature conditions (some 100 °C substrate heating) or require post‐deposition heat treatment in order to obtain high film quality. In this study, reactive low‐voltage ion plating (RLVIP) was used, which allows ‐ due to plasma assistance during the coating process ‐ deposition of ITO films at temperatures below 100 °C. Essential film properties, i.e. resistivity and optical transmission, were optimised by variation of arc current, gas pressure and deposition rate. These quantities ‐ particularly arc current and gas pressure ‐ have huge influence on the characteristics of the supporting plasma. This was shown by analysing the plasma with a mass‐spectrometric plasma monitoring system and with a Langmuir probe. In comparison with formerly studied coating materials (Ta 2 O 5 ,Nb 2 O 5 ,HfO 2 ), different plasma compositions regarding the presence of metal oxide ions were determined, which could be attributed to elemental and molecular energy properties (ionisation and binding energies).