JPS6469057A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To fine a high breakdown-strength MOSFET by burying a gate electrode and forming an offset region (layer occupying a wide area and source- drain regions (layers) on the side face of the gate electrode. CONSTITUTION:A non-single-crystal semiconductor film 13 applied onto an insulating substrate is converted into a single-crystal semiconductor film by beam annealing. A semiconductor region 26 of one conductivity type is epitaxially grown onto the single-crystal semiconductor film. An impurity of the reverse conductivity type is ion-implanted or thermally diffused into one conductivity type semiconductor region, and an offset layer 26 in concentration lower than reverse conductivity type source-drain layers and a source-drain layer 27 in concentration higher than the offset layer are shaped. The source- drain layer and the offset layer are etched up to one conductivity type semiconductor region, and a recessed section 22 is formed. A gate electrode 15 is buried into the recessed section through a gate insulating film 14, and an FET on the insulating substrate is isolated insularly. Accordingly, a high breakdown- strength MISFET having fine SOI structure is acquired, thus improving the performance of a high breakdown-strength IC.