| 摘要 |
PURPOSE:To contrive to increase the value of capacity by a method wherein a row of deep grooves or an unevenness is provided on the surface of an N (or P)- type semiconductor substrate, a P (or N)-layer is superposed, and then the P-N junction is determined as a capacitor. CONSTITUTION:The row of deep grooves 11 is formed by selectively etching the surface of the N type Si layer 10, the P-epitaxial layer 12 is superposed, windows are opened through the SiO2 film 13 of the flatted surface, and Al electrodes 14 and 15 are laid. As the angle of inclination theta of a groove is more increased, and widths (a) and (b) of the flat part are more decreased, the surface area more increases, and accordingly the P-N junction capacity more increases. When rows of grooves are provided lengthwise and crosswise, the rate of increase of the surface area becomes the second power of the case of one direction. Or, when an N<+> diffused layer 17 is provided on the surface of the deep etched groove 11, an Al electrode 19 is provided via a thermal oxide film 18, an N<+> layer 20 and an electrode 21 are provided outside the groove row region, the value of capacity can be also increased. This constitution enables to increase the value of capacity with the same area. |
