Hysteresis in volume fraction of clusters incorporated into a-Si:H films deposited by SiH4 plasma chemical vapor deposition

Susumu Toko, Yoshihiro Torigoe, Kimitaka Keya, Takashi Kojima, Hyunwoong Seo, Naho Itagaki, Kazunori Koga, Masaharu Shiratani

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

Suppressing cluster incorporation into hydrogenated amorphous silicon films deposited by SiH4 discharge plasma is the key to better film stability, because cluster incorporation contributes significantly to the formation of SiH2 bonds which are closely related to light-induced degradation of the films. Here, we report hysteresis in the deposition rate and the volume fraction of clusters incorporated into a-Si:H films deposited by SiH4 plasma CVD; the deposition rate and the volume fraction show looping behaviors when sequentially changing the discharge power, because clusters formed in the previous condition tend to remain in plasma and affect significantly the deposition rate and the volume fraction. The hysteresis is also shown as a function of SiH* emission intensity, being proportional to the radical generation rate due to electron impact dissociation of SiH4. By utilizing the hysteresis phenomenon, the volume fraction of clusters in films can be reduced significantly. We propose a model of plasma containing clusters, in which clusters play a key role in the hysteresis, namely the nonlinear behavior of the deposition rate and the volume fraction of clusters in films. Eventually, we deposited a-Si:H films of low cluster incorporation at a high deposition rate of 0.09 nm/s utilizing the hysteresis phenomena.

Original languageEnglish
Pages (from-to)388-394
Number of pages7
JournalSurface and Coatings Technology
Volume326
DOIs
Publication statusPublished - Oct 15 2017

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

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