Method for making large-surface silicon crystal bodies

Claim 3

The process of claim 1 wherein said net-like structure is comprised of a fabric formed of fibers selected from the group consisting of: (a) quartz, (b) mullite (c) graphite coated with SiO 2 , and (d) leached silica glass.

Claim 4

The process of claim 2 wherein said net-like structure is a fabric consisting of quartz fibers.

Claim 5

The process of claim 1 wherein said net-like structure is characterized by having an average mesh size in the range from about 10 to 100mm 2 .

Claim 6

The process of claim 4 wherein each said silicon body has a plate cross sectional area which is at least equal to twice said average mesh size.

Claim 7

The process of claim 4 wherein each said silicon body has a plate cross-sectional area which ranges from about 4 to 10 times said average mesh size.

Claim 8

The process of claim 1 whereinafter said crystallizing, said silicon crystal bodies are stripped from said net-like structure.

Claim 9

The process of claim 1 wherein said steps are practiced continuously.

Claim 10

The process of claim 1 wherein said net-like structure is in the form of a ribbon.

Claim 11

The process of claim 1 wherein said silicon bodies are produced by preliminarily sintering silicon powder.

Claim 12

The process of claim 1 wherein said silicon bodies are produced by spraying molten silicon onto a cooled drum.

Claim 13

The method of claim 1 wherein said heating is conducted progressively in a heating zone, and said heating zone includes a plurality of successive subzones, a first of said subzones being a silicon preheating zone, and a second of said subzones being a silicon melting zone, and wherein, in said first subzone, said silicon flat bodies are heated from above only, and wherein, after said second subzone, such resulting composite is subject to said crystallizing, and wherein, during said crystallizing, such composite is simultaneously heated from below and cooled from above.

Claim 14

A continuous process for making polycrystalline large-area silicon bodies adapted for processing into solar cells comprising in combination: (a) continuously moving a ribbon having a net-like structure wherein individual mesh sizes range from about 10 to about 100mm 2 each and which ribbon is comprised of a fibrous material selected from the group consisting of quartz, mullite, graphite coated with SiO 2 , and leached silica glass, said ribbon being horizontally oriented, said moving extending successively through each of: (1) a silicon loading zone, (2) a silicon heating zone, and (3) a silicon cooling zone, (b) in said loading zone, successively depositing along and upon said ribbon individual preformed plate-like silicon bodies in predetermined locations, (c) in said heating zone, successively first preheating said silicon forms from above and then heating the assembly of said silicon forms and said ribbon to a temperature sufficient to melt said silicon, and (d) in said cooling zone, crystallizing said molten silicon on said ribbon while simultaneously heating from below and cooling from above.

Claim 15

A continuous process for making polycrystalline large-area silicon bodies adapted for processing into solar cells comprising in combination: (a) continuously moving a ribbon having a net-like structure wherein individual mesh sizes range from about 10 to about 100mm 2 each and which ribbon is comprised of a fibrous material selected from the group consisting of quartz, mullite, graphite coated with SiO 2 , and leached silica glass, said ribbon being horizontally oriented, said moving extending successively through each of: (1) a silicon loading zone, (2) a silicon heating zone, and (3) a silicon cooling zone, (b) in said loading zone, successively depositing along and upon said ribbon individual preformed plate-like silicon bodies in predetermined locations, (c) in said heating zone, successively first preheating said silicon forms from above and then heating the assembly of said silicon forms and said ribbon to a temperature sufficient to melt said silicon, and (d) in said cooling zone, crystallizing said molten silicon on said ribbon while simultaneously heating from below and cooling from above.

Claim 16

The process of claim 13 wherein said preheating is carried out at an average temperature of about 1200° C.

Claim 17

The process of claim 13 wherein said heating is carried out at a mean temperature of from about 1000° to 1400° C. applied from below.

Claim 18

The process of claim 13 wherein said heating is carried out so as to produce graduated but symmetrical heating from the longitudinal center of each silicon body proceeding laterally to the opposing sides thereof so that heat applied to such center region terminates first while heat applied to such opposing sides terminates last as said ribbon moves through said heating zone.

Claim 19

The process of claim 13 wherein said ribbon is conveyed through said zones in contact with a graphite support.

Claim 20

The process of claim 13 wherein said ribbon continuously moves at a speed of about 50 cm/min.