skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: High-purity silicon crystal growth investigations. Final technical progress report, September 1, 1984-March 31, 1986

Abstract

This report explores a number of crystal growth effects that affect minority-carrier lifetime. The effects of impurity redistribution under the combined actions of segregation and evaporation during crystal growth were investigated mathematically. Metallic impurity reduction by evaporation is substantial during float zoning, and most metallic impurity concentrations should decrease by two to four orders of magnitude after one vacuum float-zoning pass. Two float-zoning passes in vacuum reduce most metallic impurity concentrations by more than four orders of magnitude, and three passes by more than six orders of magnitude. Minority-carrier lifetime was determined as a function of dopant density for four p-type dopants. Boron and gallium may be more favorable dopants than indium or aluminum for obtaining high lifetimes concomitant with heavy doping levels. The feasibility of achieving lifetimes greater than 100 ..mu..s at doping levels as high as 2 x 10/sup 17/ atoms/cm/sup 3/ (0.17 ohm-cm) was shown. Minority-carrier lifetime decreased as the crystal cooling rate increased in dislocation-free crystals. The dislocations, even at relatively low concentrations (2 x 10/sup 4//cm/sup 2/), drastically reduce minority-carrier lifetime. A variety of defects in dislocation-free FZ crystals and dislocated ribbons were investigated by x-ray topography.

Authors:
Publication Date:
Research Org.:
Solar Energy Research Inst., Golden, CO (USA)
OSTI Identifier:
5294268
Report Number(s):
SERI/PR-212-2926
ON: DE86010738
DOE Contract Number:  
AC02-83CH10093
Resource Type:
Technical Report
Resource Relation:
Other Information: Portions of this document are illegible in microfiche products. Original copy available until stock is exhausted
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; SILICON; CRYSTAL GROWTH; CARRIER LIFETIME; CRYSTAL DEFECTS; CRYSTAL DOPING; SILICON SOLAR CELLS; VACUUM EVAPORATION; ZONE MELTING; CRYSTAL STRUCTURE; DIRECT ENERGY CONVERTERS; ELEMENTS; EQUIPMENT; EVAPORATION; LIFETIME; MELTING; PHASE TRANSFORMATIONS; PHOTOELECTRIC CELLS; PHOTOVOLTAIC CELLS; SEMIMETALS; SOLAR CELLS; SOLAR EQUIPMENT; 140501* - Solar Energy Conversion- Photovoltaic Conversion; 360601 - Other Materials- Preparation & Manufacture

Citation Formats

Ciszek, T F. High-purity silicon crystal growth investigations. Final technical progress report, September 1, 1984-March 31, 1986. United States: N. p., 1986. Web.
Ciszek, T F. High-purity silicon crystal growth investigations. Final technical progress report, September 1, 1984-March 31, 1986. United States.
Ciszek, T F. Tue . "High-purity silicon crystal growth investigations. Final technical progress report, September 1, 1984-March 31, 1986". United States.
@article{osti_5294268,
title = {High-purity silicon crystal growth investigations. Final technical progress report, September 1, 1984-March 31, 1986},
author = {Ciszek, T F},
abstractNote = {This report explores a number of crystal growth effects that affect minority-carrier lifetime. The effects of impurity redistribution under the combined actions of segregation and evaporation during crystal growth were investigated mathematically. Metallic impurity reduction by evaporation is substantial during float zoning, and most metallic impurity concentrations should decrease by two to four orders of magnitude after one vacuum float-zoning pass. Two float-zoning passes in vacuum reduce most metallic impurity concentrations by more than four orders of magnitude, and three passes by more than six orders of magnitude. Minority-carrier lifetime was determined as a function of dopant density for four p-type dopants. Boron and gallium may be more favorable dopants than indium or aluminum for obtaining high lifetimes concomitant with heavy doping levels. The feasibility of achieving lifetimes greater than 100 ..mu..s at doping levels as high as 2 x 10/sup 17/ atoms/cm/sup 3/ (0.17 ohm-cm) was shown. Minority-carrier lifetime decreased as the crystal cooling rate increased in dislocation-free crystals. The dislocations, even at relatively low concentrations (2 x 10/sup 4//cm/sup 2/), drastically reduce minority-carrier lifetime. A variety of defects in dislocation-free FZ crystals and dislocated ribbons were investigated by x-ray topography.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1986},
month = {7}
}

Technical Report:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that may hold this item. Keep in mind that many technical reports are not cataloged in WorldCat.

Save / Share: