Browse Prior Art Database

High Quality Amorphous Silicon Film Fabrication Method

IP.com Disclosure Number: IPCOM000108830D
Original Publication Date: 1992-Jun-01
Included in the Prior Art Database: 2005-Mar-23
Document File: 2 page(s) / 76K

Publishing Venue

IBM

Related People

Pantelides, S: AUTHOR [+2]

Abstract

Described is a method fabricating high-quality amorphous silicon films for use in solar cells, thin film transistors, etc. A four-step technique is described that not only produces high quality films but produces a product that is hardened against deterioration effects.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

High Quality Amorphous Silicon Film Fabrication Method

       Described is a method fabricating high-quality amorphous
silicon films for use in solar cells, thin film transistors,  etc.  A
four-step technique is described that not only produces high quality
films but produces a product that is hardened against deterioration
effects.

      Generally, thin amorphous silicon (a-Si:H) films require low
concentrations of spin active defects.  The usefulness of these films
is somewhat limited due to deterioration, such as the
Staebler-Wronski effect, with its excess spin-active defects
generated by prolonged illumination or electric fields.  It is
believed that the defects are created at weak Si-Si bonds and that
hydrogen motion is involved in the generation and/or recombination.
If an a-Si:H film contains microvoids beyond a certain critical
concentration, the diffusion of hydrogen is completely suppressed.

      A theoretical simulation of films with microvoids indicates
that the bulk of the films have a low concentration of point defects,
i.e., dangling and floating bonds.  The floating bonds are quenched
by the microvoids, whereas the dangling bonds are trapped at their
internal surfaces.  This is consistent with results of a study (1) on
the relation between morphology, hydrogen bonding configuration, and
the spin active defect density in films deposited by radio frequency
sputtering in a wide range of sputtering conditions.  It was
concluded that H diffusion is mediated by point defects (2).  The
observed suppression of H diffusion by microvoids then implies that
the concentration of weak bonds is also suppressed since weak bonds
can thermally break and create spin a...