| 摘要 |
PURPOSE:To obtain an IC which has high reliability by separating a flat ultrafine element being manufactured as designed without using thermal oxidation for a high temperature long period nor mechanical polishing technique and forming an element on an insular region. CONSTITUTION:A hole is opened at an SiO2 film 2 on a p type Si substrate, a reactive ion etching is performed to form grooves 4. An SiO2 film 5 is covered, and a p<+> type layer 6 which has 1/2 or smaller than the width of the groove is superposed on the overall surface. Then, a p<+> type layer 6' is allowed to selectively remain by reactive ion etching on the wall surface of the groove 4, an n<-> type polysilicon 7 is superposed on the overall surface to bury the grooves 4. A p<+> type layer 8 is formed by heat treating it at a low temperature and diffusing from the layer 6 to the layer 7. When the polysilicon 7 is selectively removed with KOH, the surface of the polysilicon unit 9 becomes substantially equal level to the surface of the film 2 on an insular region, thereby completing the isolating region 10. An FET is formed as normally on the insular region. According to the method, the redistribution of the diffused layer before the step of isolating an element can be prevented, characteristics are improved, the isolating layer can be formed by a substantially defined size, and mechanical polishing is not employed. Accordingly the characteristics of the element are not degraded. |
