Trench DRAM with double-gated transistor and method of manufacturing the same

摘要

A projecting semiconductor layer is formed on a major surface of a semiconductor substrate. A channel region of a first conductivity type is formed in part of the semiconductor layer. Source and drain regions of a second conductivity type are formed in the semiconductor layer such that the source and drain regions sandwich the channel region. A pair of first insulating films are formed on a surface of the channel region. A pair of gate electrodes are formed on a surface of the pair of first insulating films. A trench capacitor is provided near the source region in the semiconductor layer. A second insulating film having a greater thickness than the first insulating films is provided between surfaces of the pair of gate electrodes, which are opposed to the surfaces on which the first insulating films are formed, and a trench capacitor formed adjacent to the trench capacitor.