ASTM F1708-96

Standard Practice for Evaluation of Granular Polysilicon by Meter-Zoner Spectroscopies

SCOPE
1.1 This practice describes a procedure to consolidate granular polysilicon into a solid rod and then to convert the polysilicon rod into a single crystal by a float-zone technique. The resultant single crystal ingot is used for the determination of trace impurities in the polysilicon. These impurities are acceptor and donor components (usually boron, aluminum, phosphorus, arsenic, and antimony) as well as substitutional carbon.
1.2 The useful range of impurity concentration covered by this practice is 0.002 to 100 parts per billion atomic (ppba) for acceptor and donor impurities, and 0.03 to 5 parts per million atomic (ppma) for carbon. The acceptor and donor impurities are analyzed in a slice taken from the single crystal ingot by photoluminescence or infrared spectroscopies. The carbon impurity is determined by analysis of a slice by infrared spectroscopy.
1.3 This practice is applicable only to evaluation of polysilicon granules as produced by thermal deposition of silane, or one of the chlorosilanes, onto high purity seeds of polysilicon in a continuous fluid bed reactor. The granules are near spherical in shape and range in size from 200 to 2500 μm with a mean size of about 900 μm.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific hazard statements are given in Section 9 and in 12.1.1.

General Information

• Status: Historical
• Publication Date: 09-Jan-2002
• ICS: 71.040.50 - Physicochemical methods of analysis
• Technical Committee: F01 - Electronics

Relations

• Replaced By: ASTM F1708-02 - Standard Practice for Evaluation of Granular Polysilicon by Meter-Zoner Spectroscopies (Withdrawn 2003)
• Effective Date: 10-Jan-2002

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or
withdrawn. Contact ASTM International (www.astm.org) for the latest information.
Designation: F 1708 – 96
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Practice for
Evaluation of Granular Polysilicon by Melter-Zoner
1
Spectroscopies
This standard is issued under the fixed designation F 1708; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope F 1630 Test Method for Low Temperature FT-IR Analysis
3
of Single Crystal Silicon for III-V Impurities
1.1 This practice describes a procedure to consolidate
2.2 SEMI Standards:
granular polysilicon into a solid rod and then to convert the
4
Specification for Gases
polysilicon rod into a single crystal by a float-zone technique.
4
Specification for Process Chemicals
The resultant single crystal ingot is used for the determination
of trace impurities in the polysilicon. These impurities are
3. Terminology
acceptor and donor components (usually boron, aluminum,
3.1 Most terms used in this practice are defined in Termi-
phosphorus, arsenic, and antimony) as well as substitutional
nology F 1241.
carbon.
3.2 Definitions of Terms Specific to This Practice:
1.2 The useful range of impurity concentration covered by
3.2.1 granular polysilicon, n—nearly spherical, granules
this practice is 0.002 to 100 parts per billion atomic (ppba) for
(200 to 2500 μm) of polysilicon as produced in a fluidized bed
acceptor and donor impurities, and 0.03 to 5 parts per million
reactor.
atomic (ppma) for carbon. The acceptor and donor impurities
3.2.2 melter/zoner, n—an apparatus designed to melt granu-
are analyzed in a slice taken from the single crystal ingot by
lar polysilicon to a solid rod and then convert the polycrystal-
photoluminescence or infrared spectroscopies. The carbon
line rod to a single crystal ingot by an rf coupled coil.
impurity is determined by analysis of a slice by infrared
3.2.3 PTFE—an acronym for polytetrafluoroethylene, a
spectroscopy.
chemically resistant polymer.
1.3 This practice is applicable only to evaluation of poly-
3.2.4 silicon pedestal, n—a piece of single crystal silicon
silicon granules as produced by thermal deposition of silane, or
cut from a high purity silicon ingot.
one of the chlorosilanes, onto high purity seeds of polysilicon
in a continuous fluid bed reactor. The granules are near
4. Summary of Practices
spherical in shape and range in size from 200 to 2500 μm with
4.1 Granular polysilicon is converted into a single crystal
a mean size of about 900 μm.
silicon rod in a two-step procedure.
1.4 This standard does not purport to address all of the
4.1.1 First, the silicon granules are consolidated into a
safety concerns, if any, associated with its use. It is the
polysilicon rod by melting fluidized granules into the molten
responsibility of the user of this standard to establish appro-
(bottom) end of a silicon pedestal during a downward pass of
priate safety and health practices and determine the applica-
the coil of the zone furnace. After about 12 g of polysilicon has
bility of regulatory limitations prior to use. Specific hazard
been melted and cooled in the zone process, a polysilicon rod
statements are given in Section 9 and in 12.1.1.
about 0.9 by 6 cm is obtained.
2. Referenced Documents
4.1.2 In the second step, a single crystal silicon seed is
2.1 ASTM Standards:
melted into the tail end of the polycrystalline rod and a single
2
D 5127 Guide for Electronic Grade Water
zone pass is done in the upward direction to level the impurities
3
F 1241 Terminology of Silicon Technology
and to convert the silicon to a single crystal rod. This produces
F 1389 Test Methods for Photoluminescence Analysis of
a single crystal silicon ingot about 0.9 cm in diameter by 5 cm
3
Single Crystal Silicon for III-V Impurities
in length from which a section is sliced for measurement of
F 1391 Test Method for Substitutional Atomic Carbon Con-
impurities. The entire consolidation and zoning requires about
3
tent of Silicon by Infrared Absorption
30 min to accomplish.
4.1.3 A slice of 2 to 4-mm thick is taken from the center
one-third of the single crystal silicon ingot for measurement of
1
This practice is under the jurisdiction of ASTM Committee F-1 on Electronics
impurities by infrared or photoluminescence spectroscopies.
and is the direct responsibility of Subcommittee F01.06 on Silicon Materials and
Process Control.
Current edition approved June 10, 1996. Published August 1996.
2 4
Annual Book of ASTM Standards, Vol 11.01. Available from Semiconductor Equipment and Materials International, 805 E.
3
Annual Book of ASTM
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