Method of forming a field effect transistor

Abstract

A method of forming a field effect transistor includes forming a channel region within bulk semiconductive material of a semiconductor substrate. Source/drain regions are formed on opposing sides of the channel region. An insulative dielectric region is formed within the bulk semiconductive material proximately beneath at least one of the source/drain regions. A method of forming a field effect transistor includes providing a semiconductor-on-insulator substrate, said substrate comprising a layer of semiconductive material formed over a layer of insulative material. All of a portion of the semiconductive material layer and all of the insulative material layer directly beneath the portion are removed thereby creating a void in the semiconductive material layer and the insulative material layer. Semiconductive channel material is formed within the void. Opposing source/drain regions are provided laterally proximate the channel material. A gate is formed over the channel material. Integrated circuitry includes a bulk semiconductor substrate. A field effect transistor thereon includes a gate, a channel region in the bulk semiconductor substrate, and source/drain regions within the substrate on opposing sides of the channel region. A field isolation region is formed in the bulk semiconductor substrate and laterally adjoins with one of the source/drain regions. The field isolation region includes a portion which extends beneath at least some of the one source/drain region. Other aspects are contemplated.