LSA large area silicon sheet task continuous liquid feed Czochralski growth. Quarterly report, July-September 1979

Technical Report · Mon Oct 01 00:00:00 EDT 1979

DOI:https://doi.org/10.2172/5629149· OSTI ID:5629149

Walters, D

This project, currently in its second phase, is directed toward the design and development of equipment and processes to demonstrate continuous growth of crystals by the Czochralski method, suitable for producing single silicon crystals for use in solar cells. Continuous is defined as the growth of at least 150 kg of monosilicon crystal, 150 mm in diameter, from one growth container. The approach to meeting this goal is to develop a furnace with continuous liquid replenishment of the growth crucible, accomplished by a meltdown system with a continuous solid silicon fedd methanism and a liquid transfer system, with associated automatic feedback controls. In order to establish process parameters for conventional CZ growth of 150 mm ingots, several runs with 12-kg charges were performed, and solidification rates of 2.7 to 3.5 kg/hr were achieved. Significant progress has been made in the development of a new melt transfer system. Basic material problems relating to the high temperature environment were solved. The cost of the new transfer mechanism is lowered substantially through multiple use of the major system components. Manufacturing of parts and installation of the polyrod feed mechanism for continuous recharging of the meltdown chamber were completed together with the feedback control system which uses the melt level sensor belonging to the growth crucible as input. The design for a continuous particle feeder into the meltdown chamber has been completed, and the fabrication of this system is currently in progress. Several short melt replenishment runs with 5 to 8 kg of continuous melt transfer were performed in an effort to develop feedback control systems for solid rod and particle feeding as well as to establish the permissible pressure region in which melt transfer can be assured.

• Research Organization: Siltec Corp., Menlo Park, CA (USA)
• Sponsoring Organization: USDOE
• DOE Contract Number: NAS-7-100-954886
• OSTI ID: 5629149
• Report Number(s): DOE/JPL/954886-79/8
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
36 MATERIALS SCIENCE
CZOCHRALSKI METHOD
EQUIPMENT
SILICON
CRYSTAL GROWTH
AUTOMATION
CONTROL SYSTEMS
CRUCIBLES
FURNACES
MONOCRYSTALS
SILICON SOLAR CELLS
CRYSTAL GROWTH METHODS
CRYSTALS
DIRECT ENERGY CONVERTERS
ELEMENTS
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
SEMIMETALS
SOLAR CELLS
SOLAR EQUIPMENT
140501* - Solar Energy Conversion- Photovoltaic Conversion
360601 - Other Materials- Preparation & Manufacture