The dependence of ECR-CVD processing parameters on deposition uniformity of hydrogenated amorphous silicon (a-Si:H) films

Li Cheng Hu, Yong Shiang Li, Chien Chieh Lee, Jeng Yang Cheng, I. Chen Chen, Tomi T. Li

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

The uniformity improvement of high deposition rate in hydrogenated amorphous silicon (a-Si:H) film deposited by electron cyclotron resonance chemical vapor deposition (ECR-CVD) is very essential for a large substrate in PV solar industry. In order to improve the uniformity in depositing thin film in large area, the auxiliary magnetic coils were designed and installed in ECR-CVD to modify the distribution of magnetic field. In addition, the dependence of the other ECR-CVD processing parameters such as resonance position, microwave power, working pressure, and substrate temperature were investigated. The results indicated that more uniform a-Si:H film could be obtained when working pressure was decreased. By using finite element analysis, it was found that location of turbo pump would impact gas flow field and this effect would become more significant at high pressure. Increasing microwave power, increasing horizontal gradient of the magnetic field to the substrate, and forming Cusp magnetic field could enhance ECR-CVD deposition uniformity greatly. However, the plasma location and substrate temperature were not major factors affecting a-Si:H film uniformity in ECR-CVD process. Finally, the optimal and the best 3.8% in uniformity could be achieved in 150mm diameter when the ratio of magnetic field strength at wafer edge to wafer center is 215%, working pressure is 1.5 mtorr, microwave power density is 4W/cm2, and substrate temperature is 180°C.

Original languageEnglish
Title of host publicationRecent Development in Machining, Materials and Mechanical Technologies
EditorsJyh-Chen Chen, Usuki Hiroshi, Sheng-Wei Lee, Yiin-Kuen Fuh
PublisherTrans Tech Publications Ltd
Pages92-100
Number of pages9
ISBN (Print)9783038354956
DOIs
StatePublished - 2015
EventInternational Conference on Machining, Materials and Mechanical Technologies, IC3MT 2014 - Taipei City, Taiwan
Duration: 31 Aug 20145 Sep 2014

Publication series

NameKey Engineering Materials
Volume656-657
ISSN (Print)1013-9826
ISSN (Electronic)1662-9795

Conference

ConferenceInternational Conference on Machining, Materials and Mechanical Technologies, IC3MT 2014
Country/TerritoryTaiwan
CityTaipei City
Period31/08/145/09/14

Keywords

  • ECR-CVD
  • Film thickness uniformity
  • Hydrogenated amorphous silicon

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