Defects in thin amorphous Si films deposited with and without Ar+ ion assistance

https://doi.org/10.1016/S0168-583X(97)00026-8Get rights and content

Abstract

Electron-beam deposited amorphous Si films on a polycrystalline Si substrate with a thickness between 10 and 500 Å were analyzed by thermal desorption spectrometry of low-energy implanted He+ ions. In addition to the standard technique, by which the film is helium-implanted after deposition, the defects were also probed by depositing layers on a substrate already containing weakly bound helium. This new method of defect decoration excludes radiation damage and makes it possible to explore deeper lying parts of the film. The desorption spectra indicate the existence of three different kinds of defects that can trap helium: interstitial volume, microvoids, and defects at the interface of amorphous and crystallized silicon.

Ar+ assistance (20–500 eV) up to an ion-to-atom arrival ratio of 0.1 was also studied. Although the distribution of interstitial volume remains basically unaffected, the microvoids virtually disappear when supplying 12 eV/atom. in the form of ion assistance.

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Cited by (6)

  • Methods of deposition of hydrogenated amorphous silicon for device applications

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    Citation Excerpt :

    In the field of PECVD of amorphous or diamondlike carbon, it is assumed that ions are of prime importance for the formation of dense material [409]. Others also stress the importance of ion bombardment on film properties [410–412]. In addition, in electron beam deposition of amorphous silicon it was shown that the formation of microvoids is inhibited when Ar+ assistance is used during deposition [413].

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