| 摘要 |
PURPOSE:To obtain a flat isolation layer as designed dimensions by a method wherein a groove is provided by etching an Si substrate by means of a three layer mask of an SiO2, an Si3N4, and a resist, an iversion prevention layer is formed, the most part of the groove is filled with SiO2, thus the substrate exposed to the inclined surface of the groove is made amorphous, and thereafter high temperature treatment is performed. CONSTITUTION:The three layer mask of the SiO2 102', the Si3N4 103', and the resist 104 is applied on the P type Si substrate 101, the groove 105 having inclination at 48-85 deg. is formed by reactive ion etching, and then inversion is prevented by providing P<+> layers 106. SiO2 107 is deposited and treated with NH4F solution, and the SiO2 107 on the side surface of the three layer mask is selectively removed by utilizing the difference of etching speeds. Next, the resist 104 and the SiO2 107 thereon are removed, and the most part of the groove 105 is filled with the SiO2 108. After O2 ions are implanted into the substrate 101 exposed to the remnant groove 105' in the periphery of the film 103', thus making the substrate amorphous 109, the isolation layer 110 is formed by performing high temperature treatment and filling the groove in a short time. This constitution enables to obtain the flat isolation layer without bird beaks, etc., and to provide the inversion prevention layer by self-alignment, resulting in the formation of a high density device. |
