| 摘要 |
A method for forming an isolation layer in a semiconductor device is provided to control a current flow through a portion under an isolation layer by making a silicon layer under the isolation layer have a shape protruding to the inside of an isolation region by a selective epitaxial growth method. An isolation formation region of a silicon substrate(200) is etched to form a trench(T). A sidewall oxide layer(203) is formed on the trench. A linear nitride layer(204) and a linear oxide layer(205) are sequentially formed on the resultant structure. The linear oxide layer, the linear nitride layer and the sidewall oxide layer are anisotropically etched to expose a part of the substrate under the trench. A silicon layer(200') is grown from the exposed substrate by a selective epitaxial growth method to fill a lower partial space of the trench. A second sidewall oxide layer is formed on the surface of the silicon layer. A second linear nitride layer and a second linear oxide layer are sequentially formed on the second sidewall oxide layer and the linear oxide layer on the sidewall of the trench. The trench whose lower partial space is filled is filled with an insulation layer.
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