METHOD OF FORMING AN ISOLATION IN FLASH MEMORY DEVICE

摘要

A method for forming an element isolation layer of a flash memory device is provided to prevent the generation of the protrusion due to the damage to a side wall by the plasma when forming a high density plasma oxide layer by forming a nitride material in a side wall of the conductive layer before forming the high density plasma oxide layer. A tunnel insulating layer(102) and a conductive layer(104) are formed in an active region. A semiconductor substrate(100) with a trench is provided in an element isolation region. A first insulating layer(110) is formed in a lower part of the trench. A second insulating layer(112) is formed in the first insulating layer including the trench and the semiconductor substrate for protecting a side wall of the conductive layer. An element isolation layer(116) is formed by forming a third insulating layer(114) inside the trench. An EFH(Effective Field Height) of the element isolating layer is controlled by a first etching process.