Copper Stable Isotope Spike Method as A Tool for Low Temperature Out-Diffusion of Copper in P-Type Silicon

摘要

A stable copper isotope, ~(65)Cu, was used as a tracer to verify quantitatively the bulk contamination and out-diffusion of copper. The sample wafers were p-type Cz Si crystals with 8.5 ～ 11.5 ohm-cm, (100) orientation and diameter of 200mm. To spike Cu isotopes, Si wafers were immersed in alkaline baths including organic amine or ammonium hydroxide spiked with ~(65)Cu isotope. IR irradiation was used to diffuse copper out of bulk Si wafers. Surface and out-diffused copper was extracted by the acid-drop method and ETV-ICP-MS was used for determination of copper. The results showed the incorporation of copper increased with the copper concentration of bath solution, and the stable isotope could be used as a tracer for the copper contamination in p-type Si wafer.