Method for fabricating semiconductor device on soi substrate

Abstract

A semiconductor device includes a plurality of single crystal semiconductor island layers formed on a semiconductor substrate with a first insulating layer intervened therebetween, the single crystal semiconductor island layers being isolated from one another by a second insulating layer. In forming the single crystal semiconductor island layers, a single crystal semiconductor layer is formed and is selectively removed on the first insulating layer. The second insulating layer is buried between adjacent ones of the single crystal semiconductor island layers. The second insulating layer is formed over the entire surface inclusive of the single crystal semiconductor island layers and a surface portion of the second insulating layer is removed by an etching process or a polishing process. Since the non-element regions are buried by the second insulating layer and the single crystal semiconductor island layers are completely isolated from one another, the substrate-related capacitances such as those at wiring regions and resistive parts are reduced.