Liquid prepn. for doping semiconductor, esp. silicon - by distilling from one vessel into sealed second vessel with constant level to give constant purity

摘要

In the prepn. of a dopant for (Si) semiconductor material, which is liq. at room temp. or contains a cpd. (POCl3) which is liquid at room temp. and decomposes at higher temp., the liquid is distilled from a first vessel into a sealed second vessel, which is kept at a constant filling level. The appts. and procedure are arranged so that the distillate in the second vessel has a constant degree of purity. The liquid is evaporated from the second vessel and the vapour is used for doping semiconductor material in a furnace, if necessary with addn. of another gas, in such a way that both the concn. of the filling ags and the concn. of all individual gas components in the furnace are kept constant and reproducible. When POCl3 is used, the appts. used for the prepn. of the dopant consists of quartz and is made in one piece. Reproducible results can be obtd. using a liquid dopant with a low degree of purity.