Semiconductor device with vertical field-effect transistor and current-sensing field-effect transistor

摘要

A semiconductor device includes a main vertical FET and a sensing FET. The main vertical FET and the sense FET are both formed on a pillar (17) of semiconductor material. Both share an extended drain region (12) formed in the pillar above the substrate (11), and first and second gate members (18) formed in a dielectric (20) on opposite sides of the pillar. The source regions (14) of the main vertical FET and the source regions (24) of the sensing FET are separated and electrically isolated. In operation, the sensing FET samples a small portion of a current that flows in the main vertical FET.