Capacitive structure producing method for use in drift zone of e.g. n-channel MOSFET, involves separating individual silicon grains from surface of trench and producing dielectric layer on silicon grains in between separated silicon grains

摘要

The method involves producing a layer (11') with silicon grains at a surface of a trench (103) of a semiconductor body (100), and separating individual silicon grains. A dielectric layer (104) is produced on the silicon grains in between the separated silicon grains, where the separation of individual silicon grains is performed by etching. The separation of the silicon grains is implemented by an oxidation step for surface proximity oxidation of the layer with silicon grains, where the dielectric layer is formed as a semi-isolating layer comprising polysilicon.