Combination gas curtains for continuous chemical vapor deposition production of silicon bodies
AssigneeMonsanto Company
InventorHenry W. Gutsche
Life of this patent
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Abstract
A process for producing electronic-grade silicon bodies is disclosed wherein continuously-pulled slim rods which can be formed in situ from the reaction of a seed crystal and a molten silicon source, are pulled into and through a chemical vapor deposition chamber, having in combination different gas curtains along the chamber inner wall, the slim rod surfaces being preheated before entry into the deposition chamber where the rods are simultaneously exposed to heating and thermally decomposable gaseous silicon compounds in order to provide suitable surface reaction conditions on the slim rods for the decomposition of the gaseous silicon compounds resulting in deposition growth upon the surfaces of the rods.
Claims21
A continuous process for preparing crystalline bodies of silicon from gaseous compounds containing silicon comprising continuously:
- a. forming a continuous virgin crystalline slim rod from a molten silicon source in a pulling chamber;
- b. heating said slim rod in said pulling chamber to the decomposition temperature of a gaseous compound containing silicon;
- c. feeding said heated slim rod directly from said pulling chamber into and through a chemical vapor deposition chamber in open communication with said pulling chamber;
- d. introducing a first gas into said chemical vapor deposition chamber near the entry point of said heated slim rod in a manner to provide a gas curtain flowing along and isolating the inner surface of said chemical vapor deposition chamber in the direction of movement of said slim rod,
- e. introducing a second gas into said chemical vapor deposition chamber near the exit point of said slim rod in a manner to provide a gas curtain flowing along and isolating the inner surface of said chemical vapor deposition chamber in a direction counter to the movement of said slim rod,
- f. contacting said slim rod in said chemical vapor deposition chamber with said gaseous compound while maintaining a temperature sufficient to decompose said gaseous compound and deposit silicon in crystalline form onto the surface of said slim rod to enlarge said slim rod;
- and
- g. withdrawing the resulting enlarge silicon body from said chemical vapor deposition chamber.
A continuous process for preparing single crystal bodies of silicon from gaseous compounds containing silicon comprising continuously:
- a. forming a continuous virgin single crystal slim rod from a continuously supplied molten silicon source in a pulling chamber;
- b. heating said slim rod in said pulling chamber to a temperature of from about 1000.degree. C. to about 1300.degree. C.;
- c. feeding said heated slim rod from said pulling chamber into a chemical vapor deposition chamber through an open communication zone between said pulling chamber and said chemical vapor deposition chamber;
- d. introducing a first gas into said chemical vapor deposition chamber near the entry point of said heated slim rod in a manner to provide a gas curtain flowing along and isolating the inner surface of said chemical vapor deposition chamber in the direction of movement of said slim rod,
- e. introducing a second gas into said chemical vapor deposition chamber near the exit point of said slim rod in a manner to provide a gas curtain flowing along and isolating the inner surface of said chemical vapor deposition chamber in a direction counter to the movement of said slim rod,
- f. contacting said slim rod in said chemical vapor deposition chamber countercurrently with a gaseous compound having the formula Si.sub.k H.sub.m X.sub.n where K is 1 to 2, m is 0-6, n is 0-6 and X is a halogen while maintaining the temperature of said slim rod at from about 1000.degree. to about 1300.degree. C. by focused radiant heat means to decompose said gaseous compound and deposit silicon in single crystal form onto the surface of said slim rod to enlarge said slim rod;
- and
- g. withdrawing and cooling the resulting enlarged single crystal silicon body from said chemical vapor deposition chamber.
Dependencies are inferred from the claim text.