Dynamic random access memory having improved layout

Abstract

A dynamic random access memory having an improved layout capable of having a large storage capacity with a small memory cell area as well as preventing the occurrence of short-circuiting by an increase in the process margin, and a method of arranging memory cells of the same. Each active region includes a first diffusion region, a second diffusion region in common with an adjacent memory cell and a channel forming region located between the first and second diffusion regions. First diffusion regions of adjacent active regions are located at positions symmetrical with respect to the common second diffusion region, at a predetermined angle. Each of uniformly spaced bit lines has a protrusion having a predetermined width and length and extending from its one edge in a direction that the word lines extend. At the protrusion, one second diffusion region is disposed. Uniformly spaced word lines cross bit lines. Each capacitor is positioned between two adjacent bit lines and between two adjacent word lines. Each first contact hole is located on the center of each capacitor. Each bit line has a bent portion for preventing a short-circuiting caused by a contact with a protrusion of adjacent bit line. Each word line has a bent portion for preventing a short-circuiting caused by a contact with each corresponding first contact hole.