The 1T cell is composed of a storage capacitor and a switching transistor for reading or writing the charge. The storage capacitance of the memory cells is affected by the sensitivity of sense amplifier, the noises and the stored charge leakage. The bottom-oxide is grown by thermal oxidation of Si substrates. The top-oxide is thermally grown on the nitride deposited by the Low Pressure-Chemical Vapor Deposited method. The use of thinner dielectric films in cell capacitors is limited by dielectric film breakdown caused by electric field dependent Fowler-Noldheim tunneling. Considerable research efforts have been made to solve these problems for each generation. Studies focused on the improvement of the breakdown characteristics and the reliability of the insulating films on the surface of tren.