| 摘要 |
PURPOSE:To obtain a high breakdown voltage element by covering the exposed substrate of the junction formed by semiconductor substrate and diffusion layer with an insrlating film, stacking high resistance layers and connecting the one end to the substrate while the other end to the diffusion layer. CONSTITUTION:When the exposed substrate of the junction formed by an n type substrate 21 and p type layer 22 is covered with the insulating layer 23, the high resistance consuctive film 24 is stacked thereon and a backward voltage is applied to both p type layer 22 and substrate 21, a very low current flows into a high resistance conductive film 24 and a potential on the film 24 linearly increases from the contact with the p type layer 22 to the contact with substrate due to a voltage drop. As a result, a high resistance conductive film works in the same way as the field plate of which voltage is linearly changing thereon, concentration of field because of the curvature of junction is drastically alleviated, an yielding voltage is very close to that in the flat junction. As explained above, a high breakdown voltage planar semiconductor device can be obtained with a very simple process and moreover increase of element area which is seen in using the protection ring structure can also be provented, with improvement in yield. |
