METHOD FOR FORMING ISOLATION LAYER OF SEMICONDUCTOR DEVICE

摘要

A method for forming an isolation layer in a semiconductor device to control an HEIP(hot electron induced punch-through) phenomenon by removing or oxidizing a part of a liner nitride layer capable of causing the HEIP phenomenon. A silicon substrate(21) is etched to form a trench(24). A sidewall oxide layer is formed on the trench. An oxide layer(26) is formed on the resultant structure. A liner nitride layer(27) is formed on the oxide layer. A first buried oxide layer(28) is formed within a scope which the trench having the liner nitride layer is not completely buried. While a partial thickness of the first buried oxide layer is etched, the first buried oxide layer is etched to remove the liner nitride layer on the upper sidewall of the exposed trench. A second buried oxide layer is buried in the trench having the first buried oxide layer to completely bury the trench. The oxide layer is made of a SiO2 layer or an Al2O3 layer by an ALD method and having a thickness of 10~100 angstroms. The liner nitride layer has a thickness of 20-100 angstroms.