| 摘要 |
PURPOSE:To greatly improve the latchup-withstanding capability by a method wherein an N<-> substrate containing a high concentration of oxygen is exposed to a high temperature for the diffusion outward of the contained oxygen and another stage of heat treatment follows for the generation of oxygen donors. CONSTITUTION:When an N<-> substrate 1 containing a high concentration of oxygen is exposed to a high temperature, of 1,150 deg.C for example, the contained oxygen is diffused outward and, when the substrate 1 is exposed to 450 deg.C for dozens of hours, oxygen donors are created. Few oxygen donors are created on the surface of the substrate 1 where oxygen is low in concentration. Oxygen is caused to be diffused outward before the formation of a P well 2. Conventional MOS- producing steps are followed, which terminate when metal is vapor-deposited for an electrode wiring 8. After the lower-temperature heat treatment for the creation of oxygen donors, the electrode wiring 8 is completed. In this design, for the same reason as the formation of an N<-> epitaxial layer on the N<-> substrate 1, the latchup-withstanding capability is enhanced. |
