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Phosphorous doping a semiconductor particle

United States Patent

July 20, 1999
View the Complete Patent at the US Patent & Trademark Office
A method (10) of phosphorus doping a semiconductor particle using ammonium phosphate. A p-doped silicon sphere is mixed with a diluted solution of ammonium phosphate having a predetermined concentration. These spheres are dried (16, 18), with the phosphorus then being diffused (20) into the sphere to create either a shallow or deep p-n junction. A good PSG glass layer is formed on the surface of the sphere during the diffusion process. A subsequent segregation anneal process is utilized to strip metal impurities from near the p-n junction into the glass layer. A subsequent HF strip procedure is then utilized to removed the PSG layer. Ammonium phosphate is not a restricted chemical, is inexpensive, and does not pose any special shipping, handling, or disposal requirement.
Stevens; Gary Don (Dallas, TX), Reynolds; Jeffrey Scott (Murphy, TX)
08/ 570,028
December 11, 1995
The Government of the United States of America has rights in this invention pursuant to Subcontract No. ZAI-4-11294-04 awarded by the U.S. Department of Energy.