Process for increasing silicon thermal decomposition deposition rates from silicon halide-hydrogen reaction gases
AssigneeMonsanto Company
InventorHenry W. Gutsche
Life of this patent
Estimating the term…
Abstract
Process for increasing silicon deposition rates from silicon halide-hydrogen reaction gases wherein electronic-grade silicon bodies are produced from the deposition of silicon upon silicon slim rods heated and introduced into and pulled through a chemical vapor deposition chamber, the increased silicon deposition rates resulting from introducing small percentages by weight of silane to the silicon halide-hydrogen reaction gases, for example, silicon tetrachloride and/or trichlorosilane.
Claims12
A continuous process for preparing bodies of crystalline silicon comprising:
- a. heating one or more silicon slim rods to decomposition temperature of gaseous silicon compounds;
- b. passing the heated silicon slim rods into a chemical vapor deposition chamber;
- c. maintaining surface temperature of the silicon slim rods from about 1000.degree. C. to about 1300 C. through heating means;
- d. contacting the silicon slim rods with a reaction gas comprised of silicon halide-hydrogen reaction gas containing from about 0.2% to about 5% by weight of silane;
- e. depositing silicon on the slim rods as the rods are moved through the decomposition chamber;
- and
- f. withdrawing the resulting enlarged crystalline silicon bodies from the decomposition chamber.
A continuous process for preparing single crystal silicon comprising:
- a. pulling a virgin slim rod in situ in a pulling chamber from the action of the seed crystal upon a molten silicon source;
- b. heating the single crystal silicon slim rod to decomposition temperatures of gaseous silicon compounds;
- c. passing the heated single crystal silicon slim rod into a chemical vapor deposition chamber;
- d. maintaining surface temperatures of the single crystal silicon slim rod from about 1000.degree. C. to about 1300.degree. C. through heating means;
- e. contacting the silicon slim rod with a reaction gas comprised of silicon halide-hydrogen reaction gas containing from about 0.2% to about 5% by weight of silane;
- f. creating a first gas curtain selected from the group consisting of hydrogen, helium, neon, argon, krypton, xenon, and radon along the chemical vapor deposition chamber inner wall, the first gas curtain flowing countercurrent to and entering an opposite zone to the reaction gas entry and flow;
- g. creating a hydrogen-chloride curtain along the inner wall in the vicinity of reaction gas entry to the decomposition chamber;
- h. depositing silicon on the surfaces of the single crystal silicon slim rod as the rod is moved through the decomposition chamber;
- and
- i. withdrawing the resulting enlarged single crystal silicon body from the decomposition chamber.
Dependencies are inferred from the claim text.