| 摘要 |
PROBLEM TO BE SOLVED: To improve device yield by imparting the gettering function to an epitaxial wafer whose resistivity is 10mΩ.cm or higher wherein formation of BMD can not be expected in device processes at a lower temperature or at a higher temperature than 1050 deg.C. SOLUTION: Corresponding to the process temperature in a device manufacturing process, heat treatment time is selected, and low temperature heat treatment is performed at 650-900 deg.C before an epitaxial film is formed. In an epitaxial wafer whose resistivity is 10mΩ.cm or higher, BMD sufficient to gettering can be formed, in a device process at a lower temperature or at a higher temperature than 1050 deg.C. Sufficient gettering to heavy metal contamination mixied by a device process is enabled. Deterioration of device characteristics which is to be caused by contamination can be prevented, and the high yield of a device is realized.
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