Improvements in and relating to processes for producing single crystals of silicon and single crystals of silicon when produced by the process

摘要

In a process for producing single n-type crystals of silicon by withdrawing a seed of silicon from a melt of silicon under a vacuum, phosphorus is added to the melt in the form of a compound of phosphorus and an element from Group IV of the Periodic Table, the compound having a lower vapour pressure than that of phosphorus alone. The compound may be one formed between silicon and phosphorus by heating them together in a closed pressure vessel at a temperature above the meltingpoint of silicon. Another compound mentioned is Sn4P3. The Provisional Specification refers to adding alloys and intermetallic compounds of arsenic, antimony and bismuth to the melt, BiCe and Bi3Ce4 being mentioned.