Ultrathin, improved SiN film, which was formed by removing the top oxide from SiO2/SiN stacked dielectric film on poly-Si, was investigated in terms of electrical properties. As a result, the ultrathin, improved SiN (top-oxide-removed SiN; T.O.R.SiN) revealed 3.8 nm SiO2 equivalent thickness and was superior to SiO2/SiN in TDDB (time dependent dielectric breakdown). This T.O.R.SiN shows promise as a dielectric film for memory capacitors in DRAMs of more than 16M bits.