| 摘要 |
PURPOSE:To obtain a highly efficient and reliable capacitance element by using an Si3N4 film and an SiO2 film converted from Si3N4 as an insulating material between electrodes. CONSTITUTION:After a mask of Si3N4 film 3 is provided on a SiO2 film 2 formed on a P type Si substrate 1 and B is implanted 4 to such mask, a thick thermal oxide film 5 is formed. At this time, an SiO2 thin film 6 is formed on the Si3N4 film 4. When a P-added poly-Si 7 is selectively provided and it is covered with an SiO2 thin film 8 and then a Si3N4 film 3 is etched, the SiO2 films 2, 6 and Si3N4 film 3 between the poly-Si 7 and substrate 1 are left as the insulating materials. The upper and lower SiO2 thin films 2 and 6 of the Si3N4 film 3 assure stable operation of a capacitance element, while the Si3N4 film becomes the fault-free condition since a fault such as pinhole is improved by the intrusion of the SiO2 film due to the thermal oxidation while a thick SiO2 film is formed. Thereby, a highly reliable capacitance element can be obtained. |
