| 摘要 |
PURPOSE: To realize a capacitor structure, wherein the area is large and the capacitance is increased by a method wherein a main depth direction trench stretches via a region of first and second material, regions of the first material and the second material have different etching characteristics, and one of the regions contains a non-silicon region. CONSTITUTION: Pure polysilicon layers 12 and polygermanium layers 14 are alternately deposited on the surface of a wafer 10 and patterned, and a main depth direction trench 16 is formed by highly anisotropic dry etching 20. The alternate layers Ge 14 of a multilayered structure are isotropically etched 22 in the lateral direction, and lateral direction trenches 18 are formed from the main depth direction trench. Similarly in the Si 12, lateral direction trenches 18' are formed from the main depth direction trench. Chemical action of etching is properly selected, and the depth direction etching and the lateral direction etching are combined. Thereby a comparatively large surface area is given to the structure, and capacitance per unit area can be increased markedly. |
