Bonded substrate of semiconductor elements having a high withstand voltage

摘要

A bonded substrate comprises a first semiconductor substrate in which a plurality of semiconductor elements are formed, a second semiconductor substrate adhered to the first semiconductor substrate so as to support it by means of an insulating layer interposed therebetween, a first semi-insulating polysilicon layer interposed between the first semiconductor substrate and the insulating layer, and a second semi-insulating polysilicon layer interposed between the insulating layer and the second semiconductor substrate. The semi-insulating polysilicon layers serve to reduce the voltage applied to the insulating layer and to prevent the insulating layer from being etched.