| 摘要 |
PURPOSE:To suppress the pitting due to a selective oxidation method by forming the desired active region in a projected shape and forming a field oxidized film which is suppressed in the pitting into the active region. CONSTITUTION:With the first Si3N4 film pattern 3' and the second Si3N4 film 18' as masks a wet oxidation is performed to selectively grow a thick oxidized film in a groove, thereby forming a homogeneous field oxidized film 20. The thickness of the film 20 at this time becomes by approx. double of the etching depth of an Si substrate such that the surfaces of the field region and the active region Si become in the same height. Since the film 18' of the side wall of the groove is formed in the bendable thickness, it is raised by the stress of the oxidized film at the field oxidizing time, and the vicinity of the boundary between the field region and the active region becomes substantially flat. Since the overhung width of the pattern 3' can be accurately controlled by the oxidizing amount of the Si substrate, the lateral spread of the field region can be suppressed. |
