| 摘要 |
PROBLEM TO BE SOLVED: To make the thickness of an oxide layer uniform by reducing crystal direction dependency as to a method for forming an oxide layer on the sidewall of a trench formed in a substrate. SOLUTION: This method has a stage, where the trench 200 is formed in the substrate 24, a stage where a nitride interface layer 1250 covering at least part of the sidewall 32 of the trench 200 is formed, a stage where an amorphous layer covering the nitride interface layer 1250 is formed, and a stage where an oxide layer 160 is formed by oxidizing the amorphous layer. Here, a separate collar 130 is arranged, by covering a separate collar nitride interface barrier layer 125 provided between a separate collar oxide layer and the trench sidewall 32, and a vertical gate oxide film 160 is arranged, covering the gate nitride interface layer 1250 provided between the gate oxide layer and trench sidewall 32. |
