Document Type

Article

Department

Physics (Pomona)

Publication Date

1-1-1993

Keywords

Silicon; Scanning tunneling microscopy (STM); Amorphous semiconductors; Surface structure; Hydrogen additions; Chemical vapor deposition (CVD); Thin films

Abstract

A scanning tunneling microscope has been used to study the topography of the as-grown surface of device-quality, intrinsic, hydrogenated amorphous silicon deposited by rf discharge from silane. The substrates were atomically flat, oxide-free, single-crystal silicon or gallium arsenide. No evidence for island formation or nanoscale irregularities was seen in studies of 100-Å-thick films on either silicon or gallium arsenide. The topography of 1000- and 4000-Å-thick films has much variation; many regions can be characterized as "rolling hills," but atomically flat areas have also been observed nearby. Generally, it appears that surface diffusion plays a role in smoothing the film topography. In most regions, the observed slopes were 10% or less from horizontal, but some steep-sided valleys, indicating incipient voids, were observed. The effect of the finite size of the scanning tunneling microscope probe tip is considered; this has an effect on the observed images in some cases.

Comments

Previously linked to as: http://ccdl.libraries.claremont.edu/u?/irw,219

Rights Information

© 1993 David M. Tanenbaum

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Terms of Use for work posted in Scholarship@Claremont.

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