Field effect transistor

Abstract

A field effect transistor formed on a semi-insulator or compound semiconductor substrate comprises a first semiconductor layer forming a source region, a drain region and a channel layer, and a second semiconductor layer having a reverse conduction type to that of the first semiconductor layer. The second semiconductor layer is doped so that it will be totally depleted. Therefore, a portion of the second semiconductor layer adjacent to the substrate will remain conductive. The field effect transistor with this structure prevents the short channel effect and the soft error due to .alpha.-particles. A threshold voltage control arrangement is also provided using the feature of a control electrode coupled to the second semiconductor layer and a feedback arrangement.