| 摘要 |
PURPOSE:To obtain the three-dimensional LSI yielding high reliability by formation of all semiconductor elements on a flat surface by a method wherein the upper surface of a gate electrode is made even with those of the source and drain regions by embedding the gate electrode on the recessed channel region. CONSTITUTION:A recrystallized Si layer 13 is formed on the insulation film 12 on an Si substrate 11, and the first Si3N4 film mask 14 is formed by a coat of Si nitride. The second Si3N4 film mask 15 is formed by another coat of Si3N4, and an SiO2 film 16 is produced. The Si3N4 film masks 14 and 15 are removed by etching, and a gate insulation film 17 is formed after high temperature oxidation. The threshold value is controlled by impurity ion implantation, and the upper surface is coated with a polycrystalline Si film 18. This film 18 is removed by polishing, and the surface is flattened by leaving the film 18 on the channel region. Since the whole comes into a flattened structure, device formation is easy and the reliability increases without possibilities such as the disconnection and short-circuit of the wiring. |
