Impurity diffusing method

Abstract

Abstract PURPOSE:To obtain normal P-N junction securely when a semiconductor wafer is held between a P type, impurity film state, diffusing source and an N type, impurity film state, diffusing source and the diffusion treatment is performed, by performing alternate lamination so that P type film is larger than the wafer and the N type film is smaller than the wafer. CONSTITUTION:A quartz rod 2 is placed on a quartz boat 1. The P type, impurity film state, diffusing source 3a whose configuration is larger than the semiconductor wafer 4 which is to be diffused is placed on the rod 2. The wafer 4 is placed thereon, and is held by the N type, impurity film state, diffusing source 5 whose configuration is smaller than the wafer 4. In this case, the diameter of the P type diffusing source 3a is larger than that of the wafer 4 by about 2mm., and the diameter of the N type diffusing source 5a is smaller by about 3mm.. Then, they are alternately layered and placed within the even heat band in the diffusing furnace, and desired diffusion is performed. In this method, even though the diffusion source 3a contracts, it does not become smaller than the wafer 4, and excessive impurities from the impurity source 5a do not reach the wafer 4.

Inventors

• 👤 Shizutaka Okubo

Bibliographic Details