METHOD OF DOPING A SILICON MEMBER

摘要

1276203 Semi-conductor devices BROWN, BOVERI & CO Ltd 14 May 1970 [16 May 1969] 23455/70 Heading H1K In order to produce a lightly doped surface layer, i.e. less than 1017 atoms /cm.3, in a silicon body, the body is first etched and washed and thereafter boiled in a solution of an oxidizing liquid including less than 5% by volume of a dopant compound, e.g. a solution of 1% by volume of orthophosphoric acid (85% concentration) in nitric acid (65% concentration) producing a doped oxide layer, and then heattreated to diffuse the dopant atoms into the body, whereafter the oxide layers are removed. A phosphorus dopant concentration of 6 Î 1016 atoms/c.c. may be obtained from the above. An alternative solution is 0À1% by volume of orthophosphoric acid in nitric acid to achieve a concentration of 5 Î 1015 atoms/c.c. Alternatively sulphuric acid may replace nitric acid as the oxidizing liquid, and for a boron diffusion boric acid replaces the orthophosphoric acid.