METHOD FOR FORMING ISOLATION LAYER OF SEMICONDUCTOR DEVICE TO PREVENT DEGRADATION OF CHARACTERISTICS DUE TO TUNNELING OF ELECTRONS IN TRAP REGION BETWEEN LINEAR OXIDE LAYER AND SILICON SUBSTRATE

摘要

PURPOSE: A method for forming an isolation layer of a semiconductor device is provided to prevent a tunneling phenomenon from a trap region by controlling a thickness of an oxide layer between a linear nitride layer of a lower part of a trench and the trap region. CONSTITUTION: A trench having a predetermined depth is formed on a silicon substrate(200) by performing an etching process after patterning a hard mask. A sacrificial oxide layer is formed into the inside of the trench and the first gap-fill oxide layer(240) is deposited thereon. The first gap-fill oxide layer is partially removed from a sidewall of the trench by performing the etching process. A linear nitride layer is formed on the first gap-fill oxide layer and the second gap-fill oxide layer(260) is deposited thereon in order to bury the trench. A polishing process is performed by using the hard mask as a polishing-stop layer.