MASK ROM OF SEMICONDUCTOR DEVICE AND FABRICATING METHOD THEREOF

摘要

PURPOSE: A mask ROM of a semiconductor device and fabricating method thereof is to restrain an auto doping of a buried impurity diffusing area, thereby reducing a space between the impurity diffusing areas to a minimum and securing a punch through margin. CONSTITUTION: A mask ROM of a semiconductor device comprises a buried impurity diffusing area(72) formed around a surface of a semiconductor substrate(70), a buried insulating layer(76) formed on the buried impurity diffusing area, a pad conductive layer(78) formed between the buried impurity diffusing areas on the semiconductor substrate to be apart from each other at an interval and arranged in one direction, and a word line(80) for covering the pad conductive layer to be orthogonal to the buried impurity diffusing areas. A method for fabricating the mask ROM comprises steps of forming a gate insulating layer on the semiconductor substrate, forming a conductive pattern on the gate insulating layer in one direction, performing an ion implanting process using the conductive layer pattern as a mask to form the buried impurity diffusing area between the conductive layer patterns, burying a space between the conductive layer patterns with an insulating material to form the buried insulating layer, forming a conductive layer for the ward line and then forming a pad conductive layer at an overlapped area of the semiconductor substrate and the ward line.