Method for fabricating a semiconductor device having a device isolation trench
View Patent ↗A method for manufacturing a semiconductor device includes forming a semiconductor substrate to have a SOI structure by an epitaxial process for forming a gate while forming an insulating film pattern in a bottom where a device isolation trench is formed. The method thereby increases the process margin for forming a device isolation film and prevents the punch-through phenomenon to improve electrical characteristics of semiconductor devices and increase product yield.
1. A method for fabricating a semiconductor device, comprising:
patterning a deposited insulating film on a bottom silicon substrate to form an insulating film pattern that exposes a region of the bottom silicon substrate;
forming an epitaxial layer on the exposed region of the bottom silicon substrate and the insulating film pattern;
partially etching the epitaxial layer to form a device isolation trench and a recess, wherein the device isolation trench defines an active region, and wherein the insulating film pattern is overlapped with both edges of the active region in a length direction and remains to form part of the semiconductor device;
forming an oxide film in the device isolation trench and the recess;
removing the oxide film in the recess; and
forming a gate in the recess.
2. The method according to claim 1 , wherein the act of partially etching the epitaxial layer comprises:
forming a hard mask pattern over the epitaxial layer; and
etching the epitaxial layer using the hard mask pattern as an etching mask.
3. The method according to claim 2 , further comprising:
removing the hard mask pattern and then performing an ion-implanting process on the active region, and wherein the act of forming a gate in the recess includes filling a conductive material over the recess.
4. The method according to claim 1 , wherein the exposed region of the bottom silicon substrate is disposed between separated portions of the insulating film pattern.
5. The method according to claim 4 , wherein:
the epitaxial layer is formed in contact with the bottom silicon substrate between the separated portions of the insulating film pattern; and
the epitaxial layer is formed in contact with exposed sidewalls of each of the separated portions of the insulating film patterns.