| 摘要 |
PURPOSE:To very easily diffuse hardly diffusible impurities by a method in which impurities are diffused from gaseous phase by providing alumina or aluminum on the surface or its neighbor of a wafer where an impurities-diffused layer is to be formed. CONSTITUTION:According to an actual example, the first and second zones of a two-stage furnace tube are kept at 750 deg.C and 1,200 deg.C, respectively, and Sb2O3 as an antimony diffusion sorce is put in a platinum box in the first zone. Also, in the second zone, wafers 1-4 are set uprightly on a jig 6 and sapphire plates 5 are arranged at an interval of (d) on the surface A where the antimony of the wafers 3 and 4 is to be diffused. As a result of the diffusion of Sb under the conditions of N2 gas as a carrier gas, a source gas concentration of 0.65mol%, d=4mm., a temperature of 1,200 deg.C, and 45min, the sheet resistance of the wafers 1 and 2 was 53OMEGA/ , and also of the surface A of the wafers 3 and 4 facing the sapphire plates 5 was 18OMEGA/ .
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