MANUFACTURE OF DYNAMIC RANDOM ACCESS MEMORY

摘要

PROBLEM TO BE SOLVED: To form a trench capacitor in a semiconductor body. SOLUTION: A trench capacitor 10 and a MOS transistor 9 are provided in a substrate 16 to form a cell 8 of the DRAM, and the cell 8 is separated from adjacent cells by an STI region 28. The capacitor 10 is composed of an insulator 14 enveloping the trench and a first electrode 24 filled with polysilicon 12, is connected to the drain portion 72 through a buried electrode 22, and is insulated from a gate electrode 20 by a dielectric 23. A second electrode 25 is formed in its bottom portion through an insulator 14. A transistor 9 has N-type drain 72 and source 71 in an upper active region 11 of the substrate 16 and operates with a p well as channel.